Change the loop behavior to something that is actually sensible,
with [ ] looping the whole playlist and [ 1 ] looping the song.
This also removes the "Do on end" setting. A new stop option may
be reintroduced, however.
This resolves issue #13.
Update the structure of the settings system to do several things:
- Finally use int preferences everywhere instead of the mix of strings & ints from before
- Create a new preference named `IntListPreference` that enables the use of integers in list preferences
- Actually centralize array values and default values into a single integers xml
- Isolate all the new migration code into a single file
- Refreshed the int tables used by data objects [DB version has been updated, will not update when other changes]
The only preference not migrated is doAtEnd since that is being planned to be retired in a future LoopMode update.
