Cleanup alsa formats definition.
Upgraded ffmpeg to 2.4.3
Increase squeezelite-1.3 revision to 498.
Port pcm decoder from trunk with audio length parsing fix for aiff.
Increase squeezelite 1.3 revision to 510
Trap large values of alsa available frames.
Increase squeezelite version to 1.3.10, revision to 511.