Add a description of ChromaTS into the software manual.

JVET-P0983/P0391: remove sps maximum sbt size flag: add configurable parameter to use 64 size SBT in encoder RDO

  - Code cleanup.

  - Fix multiplication overflow in scaled MV position.

  - Disable clipping of unscaled RPR motion vectors.

  - Disable sub-PU grouping optimization with RPR.

  - Interaction between RPR and BDOF.

  - Incorrect calculation of refHeight.

  - Incorrect clipping at picture border and insufficient picture buffer margin.

Changing variable names to not start with capital letter. Also replaced leading s_ with m_ for private, static member variables.

  - Unsafe use of reference picture PPS pointers.

I have confirmed that this modification can be consistent with the specification and there is no problem with the coding results.

Changing variable names to not start with capital letter. Also replaced leading s_ with m_ for private, static member variables.

min CU size shall be in the range of min(64, CTU size)

Patch provided by Nan Hu
Reduces LD chroma loss of JVET-O0491