Clean up README and update screenshot

README.md

@@ -4,29 +4,11 @@ Heavily inspired by Vi/Vim. Amp aims to take the core interaction model of Vim,
 simplify it, and bundle in the essential features required for a modern text
 editor.
 
+![Amp screenshot](screenshot.png?raw=true "Amp")
+
 Written with :heart: in [Rust](http://rust-lang.org).
 
 Amp's internals (data structures, syntax highlighting, workspace management, etc.)
 have been built as a separate crate: [scribe](https://github.com/jmacdonald/scribe).
 
 For a full overview, along with documentation and installation instructions, visit [amp.rs](https://amp.rs).
-
-![Amp screenshot](screenshot.png?raw=true "Amp")
-
-# Installation
-
-## Cargo
-
-If you have Rust >= 1.38.0 installed:
-
-```
-cargo install amp
-```
-
-## Homebrew
-
-You can install Amp using Homebrew:
-
-```
-brew install amp
-```