Discontinue use of Proguard

1) Significantly slows build times
2) Not much application size benefits
3) Third party libraries needed for future features do not support Proguard

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Add ContentProvider and SyncAdapter. Phase 1 of issue #103

- Initially support syncing the schedule
- Only can trigger sync with debug builds for now. Release code still
  uses old GAE behavior.
- Split some needed functionality from GAE class into utility classes.

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>