omx: Don't handle disabling/enabling ports exactly like flushing

Otherwise we might abort a flush operation in another thread when
enabling/disabling ports, leading to deadlocks sometimes.

https://bugzilla.gnome.org/show_bug.cgi?id=730989
omxvideodec: add missing stream unlock in error path
omx: Fix a missing g_free() in error path

This fixes a memory leak with g_strdup() when an error occurs.

https://bugzilla.gnome.org/show_bug.cgi?id=731141
omxvideodec: release frames with old PTS to avoid memory issue

Interlaced stream could make the decoder use two input frames to produce
one output frame causing the gstvideodecoder frame list to grow.
Assuming the video decoder output frame in display order rather than in
decoding order, this commit add a way to release frames with PTS less
than current output frame.

https://bugzilla.gnome.org/show_bug.cgi?id=730995
omxvideodec: fix a query leak

Also add a debug message if query fails.

https://bugzilla.gnome.org/show_bug.cgi?id=731898
configure: add --with-omx-header-path option for external omx headers

https://bugzilla.gnome.org/show_bug.cgi?id=726957
omxvp8dec: use VP8 definition from OMX_VideoExt.h

https://bugzilla.gnome.org/show_bug.cgi?id=726957
omxvideo: Include the separate headers too for compatibility with 1.0.x
omxh264enc: Don't let baseclass finish frames for SPS/PPS buffers

Otherwise we a) send them twice, and b) finish a frame for something
that does not even include a frame.

https://bugzilla.gnome.org/show_bug.cgi?id=726669
omxbufferpool: Properly convert OMX alignment to GStreamer alignment

GStreamer uses a bitmask for the alignment while OMX uses the
alignment itself. Let's convert.

https://bugzilla.gnome.org/show_bug.cgi?id=710564
omxbufferpool: Initialize debug category
omxbufferpool: Fix format string compiler warning
configure.ac: Require GStreamer core/base >= 1.2.2

Needed at least for gst_video_decoder_release_frame().
omx: Only include OMX_VideoExt.h conditionally

It does not exist on the RPi for example.
omxbufferpool: Copy buffers if the stride does not match and we can't use video meta

https://bugzilla.gnome.org/show_bug.cgi?id=731672
testegl: port to gstgl API

- append a glfilter just before fakesink
  So that we get gltexture or eglimages

- propagate our EGLDisplay to the pipeline
  see GST_QUERY_CONTEXT

- share our EGLContext with the iternal gl context
  of the pipeline, see GST_QUERY_ALLOCATION

- use GstVideoGLTextureUploadMeta to upload
  the incoming gltexture or eglimage to our gl texture

TODO: convert from GLESv1 to GLESv2

See https://bugzilla.gnome.org/show_bug.cgi?id=728940
testegl: convert code from GLESv1 to GLESv2

See https://bugzilla.gnome.org/show_bug.cgi?id=728940
testegl: add a comment for the parse command

See https://bugzilla.gnome.org/show_bug.cgi?id=728940
testegl: do matrix mutlplication in the shader

See https://bugzilla.gnome.org/show_bug.cgi?id=728940
example: enable testegl

See https://bugzilla.gnome.org/show_bug.cgi?id=728940