Version 2.7.0 released

[mairas]

I just released Version 2.7.0 of SensESP. The new version has some nice new features:

• It is now possible to implement SensESP apps that manage their own WiFi state without using SensESP's Networking class. This may come useful if you just want to use SensESP for its Signal K interface and ignore as much of the builtin systems as possible.
• A Button handler has been implemented that allows using a button for restarting the device, resetting the network configuration or restoring factory defaults (erasing saved network configuration and reformatting the built-in filesystem).