Allow flags to be removed.

: #ui #feature #test
Move app.coffee to base dir.

I want to keep app.coffee next to habits_engine.coffee, and that meant
either moving app or habits_engine. Since I'm not sold on separating
angular files from 'regular' JS, I'm moving app.

: #infrastructure
Remove unnecessary parens in step definitions.

This matches what Cucumber spits out when the steps are missing, and
is lighter than using parens, which aren't really needed.

: #refactor
Reordered groups to be at bottom. Added comments for some gems.

: #infrastructure
Support habit deletion.

: #feature #ui #test
Always show days of the month, even when the habits table is empty.

Also, fixes adding new habits.

: #ui #bug #test
Automatically start editing new habits.

: #ui #angular
Add focusing when you click to edit or add a new habit.

Also adjust padding on form.

: #ui
Remove margin from checkboxes.

: #ui