Rename AVFilterPicRef to AVFilterBufferRef.
The struct is going to be used for storing audio buffer references aswell, and the new name is more generic.
Patch by S.N. Hemanth Meenakshisundaram smeenaks@ucsd@edu.
Originally committed as revision 24730 to svn://svn.ffmpeg.org/ffmpeg/trunk
Make avfilter.c dprintf* functions internal and declare them in aninternal.h header, so they can be easily used from other files.
Originally committed as revision 24319 to svn://svn.ffmpeg.org/ffmpeg/trunk