Changes to get successful parsing included modification to moreRBSPData, and as a result
the Off function from the bits.BitReader. A couple of basic PPS tests have been added, but
more should be added once we know the scaling list parsing works.
Took out all VUI and HRD parameters from the SPS struct and gave them their own structs - VUIParameters and HRDParameters, along with 'contructors'
NewVUIParameters and NewHRDParameters to parse from a bits.BitReader and populate the fields of the struct.