Merge branch 'release-0.1.1' into develop
Rename variables for the song cache directory.
Add variable for directory to cache artwork.
Specifically track song downloads.
Keep track of the actual album ID in the Song class.
Add logging tag to ampacheCommunicator
Update MediaCache.cacheSong to take Song as the input.
Rename method specific to song caching
Update call to MediaCache method.
Additional helper methods for artwork caching.
Handle artwork and song downloads in the broadcast receiver.
Additional method to MediaCache for artwork.
Also check the DownloadManager status for failed downloads.
Keep track of the artwork download ID.
Make download filenames unique.

Add "song" or "art" to the front of the filename so that
the download manager doesn't run into naming conflicts. For example
if the song ID and album ID were the same value.
There may be more than one complete download.
Remove the download from the DownloadManager
This seems to properly handle both artwork and song downloads
Adding a workaround for erroneous artwork links from Ampache.
Query downloads by specific IDs. Remove extra if statement