Removed development only file. Edited README based on feedback from Matt. (+2 squashed commit)

Squashed commit:

[bd9fbf8] Updated README with dev verification code

[a4678eb] Updated to new icon from main textsecure github repo.
Added console print out for future UI error catching
Updated page to include icon on page
Merge branch 'master' of https://github.com/James-Firth/textsecure-chrome