Animated GIF looping support

Merge pull request #2 from ubiquiti/feature/gif_loop

Animated GIF looping enabled

GIF header support

v0.0.4

-- added GIF header support

GIF encoder

1. fixed GIF encoder: it allows feeding a frame from the same memory location
2. added playback timing for GIFs (it was not present at all)

Sync with upstream n4.3.1

This is n4.3.1 from upstream

Enabled GIF encoder

v0.0.1

-- enabled GIF muxer

Rebuild for libx264

v0.0.1-alpha.4

Update bump_libx264

Rebuild for libx264

v0.0.1-alpha.3

Update bump_libx264

Rebuild for bumping libx264

v0.0.1-alpha.2

-- bump_libx264

v0.0.1-alpha.1

-- ported some changes from libav