views: Cleanup signatures.
NowPlayingFragment: Refactor track information intent sharing.
Album*DataBinder: Cleanup.
MainMenuActivity: Warning cleanup.
MainMenuActivity: onCreate() refactor.
MPD: Fix potential NPEs.
WeakLinkedList: Cleanup warnings.
MPDroidService: Wind down notification prior to stop on wind down.
views: Cleanup.
MPDroid: Remove sortByTrackNumber, cleanup Music().compareTo().

This removes the sortByTrackNumber option due to developer consensus. This
fixes issue #546 by removing a potential general contract violation during
sorting. Thanks to @hurzl for the technical expertise and review of this code.
StreamHandler: A bit more logcat debug inforation.
views: Unify album cover holder naming, add AbstractCoverHolder.

This also adds a progress bar to the stored playlist list.
fragments: Document playlists fragment cleasses.

Dispite the clear naming, I've spent far too long being confused being in the
wrong fragment.