add at.js for github like emoji's, mentions, and hash tags

This may or may not be the solution used in Socializer.
quick example using at.js
make notes.js.coffee more similar to socializer
add some styling to the new note form
add a close button

still needs to be positioned
tweak the at.js code
use less
remove blank lines
change the media stylesheet to use less
consolidate toolbar properties
add quick submit button
add like to a comment
remove the close form from notes and replace it with a cancel button
expand the note form on focus as well as click
add the footer.form-actions style
clicking the new note put-on is the same as #note_content getting clicked or focus