The most important new features are AVFoundation screen-grabbing support,
animated WebP decoding support, and Animated PNG support. In addition, many
exciting features for video streaming are also implemented, including MPEG-
DASH fragmenting muxer, HEVC RTP payload muxer, and UDP Lite support.
Add -mstackrealign -mpreferred-stack-boundary=4 to CFLAGS on i386 for all
gcc 4.x versions, this appears to still be needed with gcc 4.8.4.
Bump PKGREVISION for ffmpeg2 and ffplay2 (which uses ffmpeg2 patches)
