Clean up DBUtils.updateUnwatchedCount().

- Cursor null checks.
- Inline static int arguments.
Clean up TraktSync, handle cursor null pointer.

- Added TraktSyncQuery interface.
- Add FAILED status message if Cursor was null.
Use EpisodeFlags constants instead of hard coding.

- In UpcomingFragment, EpisodesAdapter and SearchResultsAdapter.
Support skipping in overview.

- Also add cheat sheet to check in button.