JVET-R0214: MMVD syntax modifications
JVET-R0214: All aspects with change of flag rather than additional flag.
- Move the location of sps_mmvd_fullpel_only_flag to directly follow sps_mmvd_enabled_flag.
- Infer the value of sps_mmvd_fullpel_only_flag to be equal to 0 when the flag is not present.
- Replace/rename the current flag no_fpel_mmvd_constraint_flag to no_mmvd_constraint_flag and change the semantics accordingly.
The third aspect is partly covered by the already merged JVET-R0286 (which includes adding a new no_mmvd_constraint_flag), thus the code for the third aspects only removes things around no_fpel_mmvd_constraint_flag