Add auto expand to work unit notes under time clock;

Creates a hidden div with the same dimensions as the text area input. Uses JS to measure the hidden div height and apply the new height to the text area.
Refactor JQuery to ninjascript

[#40]
Merge pull request #63 from TimePulse/auto_expand_notes_40

Auto expand notes 40
Add json serializer and mapper to work units. 

Added json_spec to Gemfile. There is a problem with accepting both params and json strings in a post create that would probably be solved by updating to Rails 4. Should come back to this branch when the update is complete.
Fix merge conflicts
Rails 4 upgrade

Also includes json api
Fix merge conflicts