API changes, most recent first:
+2017-03-21 - xxxxxxx - lavf 57.66.105, lavc 57.83.101 - avformat.h, avcodec.h
+ Deprecate AVFMT_FLAG_KEEP_SIDE_DATA. It will be ignored after the next major
+ bump, and libavformat will behave as if it were always set.
+ Deprecate av_packet_merge_side_data() and av_packet_split_side_data().
+
2016-03-20 - xxxxxxx - lavu 55.50.100 / 55.21.0 - imgutils.h
Add av_image_copy_uc_from(), a version of av_image_copy() for copying
from GPU mapped memory.