Initial commit, using shared OpenGL texture with gst-plugin-gl so only one video pipeline running.
Removed gst-plugin-gl elements and use decodebin2 to get multiple video pipeline instances working, with audio.
YUV to RGB conversion in a GLSL shader added.
Made yuv2rgb shader modular and added colour higlighting shader.
Added alpha masking texture support.

Cleaned up texture configuration, added demo code to load alpha textures
and shaders for blending videos together.
Moved the source into a subdirectory.
Added glm library to load Wavefront OBJ model files into the demo.
Updated glm to optionally use texture ID specified by application through new API call.
Added OBJ model loading support to POC demo, can texture model with video 0.
Updated default model directory definition.
Added qt_widget_gl_scene demo for viewing widgets in perspective projection using QGraphicsView, based on wolfenqt.
Only shows rectangles at the moment as widget painting isn't working for some reason.
Got qt_widget_gl_scene to display some widgets with correct transformations, forgot to initialise the m_scale variable which threw things off for a while.
Needs a good tidy up now.
qt_gl_gst: disabled use of libglm, added use of assimp library.
Can now draw models using vertex arrays in preparation for OpenGL|ES.
Also added QMatrix4x4 but not switched to using those instead of GL matrices yet.
qt_gl_gst: cleaned up code a bit.
Removed glm library now that it is no longer being utilised.
qt_gl_gst: Got model to display using QMatrix4x4 instead of GL matrices. This is the next step
towards GL|ES compatibility. The code is a real mess now but preserve it while its working!
Lighting of the model isn't right as normal matrix isn't right either.
qt_gl_gst: Got specular lighting working in (hopefully) GL|ES compatible manner,
by computing reflection vector without GLSL reflect() function.
Using a QMatrix4x4 in model class created from assimp equivalent.
Matrix code clean up.
qt_gl_gst: Switched videos to render using vertex arrays with triangle strips
instead of quads, and matrices passed to shaders. GL transformation calls should
now be going unused.
Need to modify video effects shaders before they will work.
qt_gl_gst: Removed GL transformation code, demo now builds for GLES2 on the
OMAP3530 DVSDK, but is not tested.
Comments cleaned up.
qt_gl_gst: Got video texture on the model working again with GLES.