Update RaspiStill framework to provide access to the new EGL image
targets that provide a fastpath for mapping the individual YUV planes to
one byte per pixel GL_LUMINANCE buffers. These are still accessed as OES
textures so this is effectively a greyscale image created from a single
plane of a MMAL buffer.
Also added some example code (yuv, sobel) that demonstrates how to use
the new EGL image targets.
Also, add -gc to the command line to capture the GL frame-buffer as a TGA file.
Thanks to Tim Gover
Add RaspiTex.c which demonstrates how the camera preview buffers can be
bound to EGL Images and rendered via Open GLES.
To enable GL rendering add --gl to the command line and select a
GL scene
* square - A simple rotating square
* teapot - The classic teapot demo
* mirror - OpenGL ES 2.X Hall of mirrors example
