Move podcast logo deletion to PodcastPersistence
Move episode file deletion to EpisodePersistence
Fix typo in method name
Do not copy the logo to another location
Typo in DetlefDownloadManager
Ensure podcast logos are not picked up by gallery
Remove silly try/catch block
Do not update the DB twice on download completion
Remove UNWANTED_CHARS clutter
Begin refactoring download manager

Split handling for different files into callbacks.
Finalize download manager refactoring
Move download callbacks to appropriate spots
Update the episode storage state on deletion

The file and DB handling is somewhat confused.
Sometimes, DB functions delete files, which they shouldn't; sometimes,
file persistence functions update the DB, sometimes they don't. This
needs some further refactoring.
Update a download manager testcase
Update test case and documentation for local DB methods

These are not guaranteed to return references to the same object on
repeated calls.
Remove the global DB lock

The DatabaseHelper is synchronized itself, therefore we can get by by
using only a single instance of it. Since we are now using the same
database connection all over the application, we only close it when
MainActivity is destroyed.
Remove noisy debug output
Update the TODO file
Pause playback on PHONE_STATE and HEADSET_PLUG

This receiver is responsible for pausing playback if a headset is
unplugged or a call is started.