Implemented simple stopwatch
Refactor model/watch
Save timer progress
Don't save total number of seconds
Refactor: move updating total time to watch view
Format time
Added commenting of the watch
Added multiple watches
Use collection instead of model
Save state of all timers
Sprint title saving & validation
Add preferred watch
Show preferred watch on load
Add default watch when creating new sprint
Add badge with stopwatch
Normal updating of sprint watch children
Get rid of excessive model flags
Make body entry point of the application
Change extension structure
Change inheritance structure