vaapisink: implement the GstNavigation interface

This is useful for things like DVD menus, where key/mouse events
would need to be forwarded from the upstream sink element.

https://bugzilla.gnome.org/show_bug.cgi?id=711479
vaapisink: fix GstNavigation "mouse-move" event.

Really use the motion event coordinates to propagate the "mouse-move"
event to upper layer, instead of those from a button event. Those are
technically the same though.
vaapisink: fix GstNavigation "key-press" / "key-release" events.

Fix arguments to XkbKeycodeToKeysym() for converting an X11 keycode
to a KeySym. In particular, there is no such Window argument. Also
make sure to check for, and use, the correct <X11/XKBlib.h> header
where that new function is defined. Otherwise, default to the older
XKeycodeToKeysym() function.
vaapisink: clean-ups (indentation, drop unused variables).
display: add support for DRM Render-Nodes.

Add support for DRM Render-Nodes. This is a new feature that appeared
in kernel 3.12 for experimentation purposes, but was later declared
stable enough in kernel 3.15 for getting enabled by default.

This allows headless usages without authentication at all, i.e. usages
through plain ssh connections is possible.
configure: echoing installation prefix path
encode: Attach the codec-data to out caps only based on negotiated caps

Attach the codec_data to out_caps only if downstream needed.
For eg: h264 encoder doesn't need to stuff codec_data to the
src caps if the negotiated caps has a stream format of byte-stream.

https://bugzilla.gnome.org/show_bug.cgi?id=734902
vaapidecode: Expose the supported profiles as caps to upstream

This will allows the playbin to fallback to Software Decoder
if the Hardware Decoder does not support a particular profile.

https://bugzilla.gnome.org/show_bug.cgi?id=730997
codecparsers: update to gst-vaapi-branch commit f9d3bde.

2218b02 h264parse: expose parsed profile and level to downstream
3dbfab4 h264parse: return flushing if we get chained while being set to READY
d40fa8b h264: fix frame packing SEI parsing
32d40be h264: Use proper bit_reader api while parsing buffering_period SEI
b3e022e h264: initialize some fields of pic_timing structure
a70661d vc1: fix expected level in sequence-layer parsing unit test
6cee88d vc1: fix level values for simple/main profile
356c189 vc1: add unit test for sequence-layer parsing
ab9f641 vc1: take care of endianness when parsing sequence-layer
8dc8e35 mpeg4: fix vlc table used for sprite trajectory
filter: re-indent all GstVaapiFilter related source code.
filter: add initial support for high quality scaling.

Add support for video scaling options in VPP pipelines. Only the
DEFAULT mode is bound to exist. Others might be folded into that
mode.
vaapipostproc: allow user defined scaling mode.

Add new "scale-method" property to expose the scaling mode to use during
video processing. Note that this is only a hint, and the actual behaviour
may differ from implementation (VA driver) to implementation.
vaapipostproc: Tweak the output video format setting to enable the autoplugging

This is a workaround until auto-plugging is fixed when
format=ENCODED + memory:VASurface caps feature are provided.

Use the downstream negotiated video format as the output video format
if the user didn't ask for the colorspace conversion explicitly.
Usecase: This will help to connect elements like videoscale, videorate etc
to vaapipostproc.

https://bugzilla.gnome.org/show_bug.cgi?id=739443
vaapipostproc: Add string representation of VPP functions to ElementFactoy Klass

Added the same Klass specifications used in other upstream
video postprocessing elements like videoconvert, videoscale,
videobalance and deinterlace.
An example use case is for this is to help the playsink
to autoplug the hardware accelerated deinterlacer.
codecparsers: update to gst-vaapi-branch commit 3d05d9f.

1241840 h264: fix derivation of MaxPicNum variable
3bd718e h264: fix GstH264ParserResult documentation typo
b021609 h264parse: set the HEADER flag on buffers containing SPS or PPS
b08e4be h264parse: don't unnecesarily set src_caps
decoder: h264: fix detection of top-field-first (TFF) flag.

Use the SEI pic_timing() message to track the pic_struct variable when
present, or infer it from the regular slice header flags field_pic_flag
and bottom_field_flag. This fixes temporal sequence ordering when the
output pictures are to be displayed.

https://bugzilla.gnome.org/show_bug.cgi?id=739291
decoder: h264: fix picture ordering count type 0 with previous MMCO5.

Fix the decoding process for picture order count type 0 when the previous
picture had a memory_management_control_operation = 5. In particular, fix
the actual variable type for prev_pic_structure to hold the full bits of
the picture structure.

In practice, this used to work though, due to the underlying type used to
express a gboolean.
decoder: h264: add initial support for repeat-first-field (RFF) flag.

Use the SEI pic_timing() message to track and propagate down the repeat
first field (RFF) flag. This is only initial support as there is one
other condition that could induce the RFF flag, which is not handled
yet.
vaapidecode: only expose supported profiles when needed.

JPEG and VP8 codecs do not really support the concept of "profile". So,
don't try to expose any set that wouldn't be supported by jpegparse, or
ivfparse for instance.

https://bugzilla.gnome.org/show_bug.cgi?id=739713
https://bugzilla.gnome.org/show_bug.cgi?id=739714
vaapidecode: increase the rank to GST_RANK_PRIMARY + 1

This is for helping decodebin to autoplug the vaapidecode element.

Decodebin is selecting decoder elements only based on rank and caps.
Without overriding the autoplug-* signals there is no way to autoplug
HW decoders inside decodebin. An easier soulution is to raise the
rank of vaapidecode, so that it gets selected first.

https://bugzilla.gnome.org/show_bug.cgi?id=739332