GLMixer Code

Add media access to side bar of file dialog.

Fix compilation older ffmpeg libavcodec underx linux.

Preliminary implementation of directx VA2 hardware acceleration under Windows

preliminary implementation of hardware codec decoding under OSX

Improved listing of volumes in custom file dialogs

BugFix: no change to source when cancel custom mask file.

BugFix: display error message on error creating basket source.

Added preference option to disable the hardware codec. Improved file open
dialog to offer option to enable/disable hardware codec. Default to
disabled hardware codec.

BugFix (Ticket #75 GLMixer Control panel window stretches off of
screen.): information text in status bar eluded to fit in window.

Updated File Dialog to offer option to use GPU decoding.