GLMixer Code

Bug Fix: removing remaining tests in glmixer source edit

Simplified Media Source and Video File implementation. Removed option
'Seek dirty frames' which was useless and buggy.

Finalize the re-implementation of VideoFile without the parsing thread.
Fixed the seek mechanism.

Removing Parsing thread in VideoFile: I surrender in finding how to
avoid memory leak in the packet queue... This new implementation reads
packet and decodes picture in the same thread. Memory leak seems fixed
(althouth i am not fully satisfied). NOT STABLE FOR SEEKING.

Bug Fix: reading info on rendering size (width, height) from
RenderingManager was dependent on initialization of fbo, causing error
when fbo was reset. (this also fix the reading of SVG source).

Bug Fix: cleanup implementation VideoPicture Memory Map

Implementation of memory map (mmap) for memory management of
VideoPicture memory allocation.

Bug Fix: re-set resetPicture after updating firstPicture.

Bug Fix: properly deleting firstPicture (instead of filling it in
without clearing buffer).

Bug Fix: Looks like memory management is now fixed. Memory is freed from
libav internal structures and glmixer buffers (picture queue and packet
queue). Something still wrong with start/stop, which does not seem to
free memory immediately (but is freed when closing).