Remove Twitter configuration file.
Remove references to Twitter from non-theme files.
Remove Twitter Timeline CoffeeScript.
Do not require twitter in site.coffee.
Remove Twitter timeline SCSS.
Bring back Twitter configs when needed for 'tweet' button (for posts).
Removed twitter sidebar section.
Remove mention of ADN in Readme.
Merge pull request #1101 from imathis/bye-twitter

Bye, Twitter Timeline