chore(.gitignore): ignore bower_components directory
feat(commenter): create base assets for commenter directive in demo
fix(commenter): create partial view for commenter directive [demo]
feat(githubService): implement githubService in demo application

This service adds some cuteness to the application, primarily used as a way of
autocompleting usernames, and fetching gravatar images for commenters. It doesn't
do much beyond that, but it's a start.
fix(app.css): add style for typeahead directive [demo]

Make the typeahead stuff a bit nicer.
fix(app.css): style invalid form controls and typeahead content

Maximum prettification
feat(commenter): support adding new comments in demo application

Unfortunately, this does not currently push any data anywhere, it would be nice
to add support for that later on. It should also probably not show this button
in the Reddit demo, since we certainly aren't pushing comments to Reddit.

However, it's super cool and works pretty well, awesome.

Closes #28