Missions open and close!

* Missions open when they are created and close 24 hours later
* They stop being open_for_voting after 48 hours
* Viewing a mission that is closed, there is no "doodle it" button
* Also removed home controller. It wasn't doing anything missions#index couldn't do
* NOTE TO SELF: give css classes better names
Doodles are polymorphic!
For some reason everything is terrible now
Switched fog gem to carrierwave-aws and now it works! Thanks carrierwave!
Changed javascript to work with new polymorphic doodles
Users can draw their profile pictures!
rearranging some view stuff
Users can add friends! At last!
Moved canvas environment to a handlebars template.

* Building it in jquery sucked.
The start-over button now works again