Patches to bring gst-libav-1.14.4 up to git master 1.15.x state at 20181115,
while keeping it compatible with gstreamer-1.14.
Skipped patches include:
* git submodule updates - we don't need gas-preprocessor, as it's only for
  some OSX + architecture + asm combinations; common/ doesn't have any important
  updates over what's included in 1.14.4 tarball.
* Version and others updates for 1.15
* Patches that update files only found in git
* Patches that already exist on 1.14.4 from upstream cherry-picks
* Commit b894bedeb3d47c25 (avvidec: Expose Closed Caption as GstVideoCaptionMeta),
  as it relies on new 1.15 API

Changed patches:
* 0006 version changed from 1.15.0.1 to 1.14.4 for the hunk to apply cleanly
  without the earlier patch that updated version to 1.15.0.1; also meson_version
  changed from 0.36.0 to 0.40.1 for similar reasons (1.14 branch had it updated).
* 0011 removed removal of #include for a header that the skipped patch of commit
  b894bedeb3d47c25 added.
* 0015 removed hunk for gstavscale.c, which isn't shipped in tarball and later
  removed in git altogether.
* 0028 - CAT_PERFORMANCE → GST_CAT_PERFORMANCE as 1.14.4 has that change backported
  separately.
* 0032 - same as 0028
