JMPDComm: Fix a few miscellaneous performance warnings.
Music.java: Refactor timeToString().
NowPlayingSmallFragment: Fix the no coverart after valid coverart.
NowPlayingFragment: Remove timeToString, use the method from Music.java.
Music.java: Remove dead toString() code, document it.
JMPDComm: Remove version/author Javadoc lines, they make no sense anymore.

With VCS technology being what it is now, Javadoc author/version make no sense
anymore.
PlaylistFile: Cleanup PlaylistFile, fix warnings.

Cleanup PlaylistFile, fix warnings, including moving a regexp to a final
static space to be compiled prior to running.
NowPlayingFragment: Seed MPDStatus on connection or resume.

Prior to this, the status was kept up to date due to how many times
updateTrackInfoAsync() would get hit in the beginning. After this behaviour
was cleaned up the status would regularly be out of sync, this should
fix that.

The only two places the MPDStatus should need to be updated, outside
of the idle status monitor is connectionStateChanged() or onResume().
MPDStatusMonitor: When updating, the status is changing, not the database.

According to MPD Protocol Reference, Chapter 3, the server will emit an update
idle response to an update command. This does not mean the database has
actually changed, only that the server is checking for updates, making this
an actual status change.
MPDStatusMonitor: Let the user know if the database actually changed.

Let the user know if the database actually changed. This will only happen after
the first parameter of libraryStateChange has changed to true to false.
StringUtils: Remove unused and trivial method.
CachedCover: Cleanup some duplicated code.
StreamingService: Allow onCompletion to complete the stream in more cases.

Do better at detecting the final song and on stop letting it finish rather
than abruptly shutting off.
NowPlayingSmallFragment: Prevent exceptions not added to the current activity.
NowPlayingSmallFragment: Prevent NPEs in stateChanged().
MPD.java: When possible return at the end of the method.
MPDroid: Use app singleton.
JMPDComm: Clean up a few warnings.
JMPDComm: Use explicit numeric assignment to avoid implicit numeric conversion.
MPDStatistics: Refactor with if block conversion to switch.