Use some of the SDP attributes when they are present to specify the output
dimension and framerate. This allows us to receive jpeg frames larger than
2040 width/height.
Fixes#564437
Use the width and the height from the payload headers and set them on the
output caps for added awesomeness.
Fix quant parsing, we need to check the type in the lower 6 bits.
Add first bits of caching quantization tables.