API changes, most recent first:
+2017-09-01 - xxxxxxx - lavf 57.80.100 / 57.11.0 - avio.h
+ Add avio_context_free(). From now on it must be used for freeing AVIOContext.
+
+2017-08-08 - xxxxxxx - lavu 55.74.100 - pixdesc.h
+ Add AV_PIX_FMT_FLAG_FLOAT pixel format flag.
+
2017-08-08 - xxxxxxx - lavu 55.72.100 - imgutils.h
Add av_image_fill_black().