Doc fixes (#3333)

Author: HHHartmann

CONTRIBUTING.md

@@ -78,7 +78,7 @@ As a Windows or Mac user you could also resort to [GitHub Desktop](https://deskt
 You need to sync your fork with the NodeMCU upstream repository from time to time, latest before you rebase (see flow above).
 
 1. `git fetch upstream`
-1. `git checkout dev` but you may do this for `master` as well
+1. `git checkout dev` but you may do this for `release` as well
 1. `git merge upstream/dev`
 
 ### Commit messages
@@ -114,8 +114,8 @@ Don't forget to [reference affected issues](https://help.github.com/articles/clo
 - Add notes to the description of the milestone in the course of the ~2 months it lives.
 - Be careful and reluctant to merge PRs once we're past the 6-weeks mark of a milestone. Ideally, we don't merge anything in the last 2 weeks.
 - Cutting a release
-    - Create a PR for the `master` branch for collaborators to approve.
+    - Create a PR for the `release` branch for collaborators to approve.
     - Once approved merge it. :exclamation::boom::exclamation: Make sure you do NOT "squash and merge" but make a regular merge commit!
-    - Fetch the changes into your local clone and create an annotated tag like so: `git tag -a <SDK-version>-master_<yyyyMMdd> -m ""`, `git push --tags`
+    - Fetch the changes into your local clone and create an annotated tag like so: `git tag -a <SDK-version>-release_<yyyyMMdd> -m ""`, `git push --tags`
      - Create a new [release](https://github.com/nodemcu/nodemcu-firmware/releases) based on the tag you just pushed. The version name is the same as the tag name.
      - Write release notes. Mention breaking changes explicitly. Since every PR that went into this release is linked to from the milestone it should be fairly easy to include important changes in the release notes.

README.md

@@ -2,8 +2,8 @@
 
 [![Join the chat at https://gitter.im/nodemcu/nodemcu-firmware](https://img.shields.io/gitter/room/badges/shields.svg)](https://gitter.im/nodemcu/nodemcu-firmware?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![Build Status](https://travis-ci.org/nodemcu/nodemcu-firmware.svg)](https://travis-ci.org/nodemcu/nodemcu-firmware)
-[![Documentation Status](https://img.shields.io/badge/docs-master-yellow.svg?style=flat)](http://nodemcu.readthedocs.io/en/master/)
-[![License](https://img.shields.io/badge/license-MIT-blue.svg?style=flat)](https://github.com/nodemcu/nodemcu-firmware/blob/master/LICENSE)
+[![Documentation Status](https://img.shields.io/badge/docs-release-yellow.svg?style=flat)](http://nodemcu.readthedocs.io/en/release/)
+[![License](https://img.shields.io/badge/license-MIT-blue.svg?style=flat)](https://github.com/nodemcu/nodemcu-firmware/blob/release/LICENSE)
 
 ### A Lua based firmware for ESP8266 WiFi SOC
 
@@ -14,9 +14,9 @@ The firmware was initially developed as is a companion project to the popular ES
 # Summary
 
 - Easy to program wireless node and/or access point
-- Based on Lua 5.1.4 but without `debug`, `io`, `os` and (most of the) `math` modules
+- Based on Lua 5.1.4 or Lua 5.3 but without `debug`, `io`, `os` and (most of the) `math` modules
 - Asynchronous event-driven programming model
-- more than **65 built-in modules**
+- more than **70 built-in C modules** and **close to 20 Lua modules**
 - Firmware available with or without floating point support (integer-only uses less memory)
 - Up-to-date documentation at [https://nodemcu.readthedocs.io](https://nodemcu.readthedocs.io)
 
@@ -48,23 +48,23 @@ wifi.sta.config{ssid="SSID", pwd="password"}
 
 The entire [NodeMCU documentation](https://nodemcu.readthedocs.io) is maintained right in this repository at [/docs](docs). The fact that the API documentation is maintained in the same repository as the code that *provides* the API ensures consistency between the two. With every commit the documentation is rebuilt by Read the Docs and thus transformed from terse Markdown into a nicely browsable HTML site at [https://nodemcu.readthedocs.io](https://nodemcu.readthedocs.io).
 
-- How to [build the firmware](https://nodemcu.readthedocs.io/en/master/en/build/)
-- How to [flash the firmware](https://nodemcu.readthedocs.io/en/master/en/flash/)
-- How to [upload code and NodeMCU IDEs](https://nodemcu.readthedocs.io/en/master/en/upload/)
+- How to [build the firmware](https://nodemcu.readthedocs.io/en/release/build/)
+- How to [flash the firmware](https://nodemcu.readthedocs.io/en/release/flash/)
+- How to [upload code and NodeMCU IDEs](https://nodemcu.readthedocs.io/en/release/upload/)
 - API documentation for every module
 
 # Releases
 
-Due to the ever-growing number of modules available within NodeMCU, pre-built binaries are no longer made available. Use the automated [custom firmware build service](http://nodemcu-build.com/) to get the specific firmware configuration you need, or consult the [documentation](http://nodemcu.readthedocs.io/en/master/en/build/) for other options to build your own firmware.
+Due to the ever-growing number of modules available within NodeMCU, pre-built binaries are no longer made available. Use the automated [custom firmware build service](http://nodemcu-build.com/) to get the specific firmware configuration you need, or consult the [documentation](http://nodemcu.readthedocs.io/en/release/build/) for other options to build your own firmware.
 
 This project uses two main branches, `release` and `dev`. `dev` is actively worked on and it's also where PRs should be created against. `release` thus can be considered "stable" even though there are no automated regression tests. The goal is to merge back to `release` roughly every 2 months. Depending on the current "heat" (issues, PRs) we accept changes to `dev` for 5-6 weeks and then hold back for 2-3 weeks before the next snap is completed.
 
-A new tag is created every time `dev` is merged back to `master`. They are listed in the [releases section here on GitHub](https://github.com/nodemcu/nodemcu-firmware/releases). Tag names follow the \<SDK-version\>-master_yyyymmdd pattern.
+A new tag is created every time `dev` is merged back to `release`. They are listed in the [releases section here on GitHub](https://github.com/nodemcu/nodemcu-firmware/releases). Tag names follow the \<SDK-version\>-release_yyyymmdd pattern.
 
 # Support
 
-See [https://nodemcu.readthedocs.io/en/master/en/support/](https://nodemcu.readthedocs.io/en/master/en/support/).
+See [https://nodemcu.readthedocs.io/en/release/support/](https://nodemcu.readthedocs.io/en/release/support/).
 
 # License
 
-[MIT](https://github.com/nodemcu/nodemcu-firmware/blob/master/LICENSE) © [zeroday](https://github.com/NodeMCU)/[nodemcu.com](http://nodemcu.com/index_en.html)
+[MIT](https://github.com/nodemcu/nodemcu-firmware/blob/release/LICENSE) © [zeroday](https://github.com/NodeMCU)/[nodemcu.com](http://nodemcu.com/index_en.html)

docs/build.md

@@ -28,7 +28,7 @@ If you decide to build with either the Docker image or the native environment th
 ```
 git clone --recurse-submodules -b <branch> https://github.com/nodemcu/nodemcu-firmware.git
 ```
-Omitting the optional `-b <branch>` will clone master.
+Omitting the optional `-b <branch>` will clone release.
 
 ## Build Options
 
@@ -104,7 +104,7 @@ either by uncommenting `LUA_NUMBER_INTEGRAL` in `app/include/user_config.h`:
 ```
 
 OR by overriding this with the `make` command as it's [done during the CI
-build](https://github.com/nodemcu/nodemcu-firmware/blob/master/.travis.yml#L30):
+build](https://github.com/nodemcu/nodemcu-firmware/blob/release/.travis.yml#L30):
 
 ```
 make EXTRA_CCFLAGS="-DLUA_NUMBER_INTEGRAL ....