Re-style pomodoro index, implement test

Change styling on pomodoro index to distinguish between
productive periods and breaks. Implement acceptance test.
Add integration test
Implement paused animations and disabled buttons
Pause progress bar animations, implement presenter

Progress bar animation now pauses on pomodoro pause. Implement
presenter for pomodoro view logic.
Implement 'User sees breaks'

Add period attribute to Pomodoros. Implement period-specific
styles on pomodoro index view.
Implement email message and bodies based on period

Pomodoro notification emails are now customized based on
the activity that has been completed. Removed extraneous autoload
statements from application.rb.