Added share on twitter sunctionality

Honestly... much more trouble than it was worth. Couldn't use the plugin
provided by Twitter as it would render in a way that you couldn't change
the href on runtime, so had to make a custom link and custom button and
copy the real button's css. Used this
http://codepen.io/alistairtweedie/pen/JlFnq but had to customize a
little as theirs wasn't actually very good. Functionality:
1) If no acronym loaded: will open new tab and suggest tweeting "TLA -
Three Letter Acronyms, just for you! http://tla.herokuapp.com/ #TLA"
2) if acronym loaded, will open new tab and suggest tweeting "kkk:
Keeled Kurchi  Keeper http://tla.herokuapp.com/ #TLA" (or whatever
acronym presently loaded)
Removed hard-coding of url
Merge remote-tracking branch 'upstream/master'
Rewrote twitter link using MVVM

Twitter link is now dynamically updated like the rest of the app
Readded onBlur
Merge pull request #8 from kadikraman/master

Added share on twitter functionality