This is for the case where JVET_M0464_UNI_MTS is disabled

Code was salvaged from !306

Merge functionality from HM (macro JCTVC_Y0038_PARAMS). Add an additional
configuration file parameter that allows re-sending parameter sets at every
random access point.

Speed-Up for ISP when JVET_M0464_UNI_MTS is enabled. It can be enabled/disabled with the config. file parameter ISPFast.

When enabled,
-it merges all full RD intra mode lists into one,
-it tests fewer non-DCT-II transforms if ISP is likely to become the best mode and
-it stops testing intra modes for an ISP split if all sub-partitions obtained a zero-cbf.

Results in CTC:

AI -> 0.04% loss, EncT = 97%, DecT = 100%
RA -> 0.01% loss, EncT = 99%, DecT = 100%

compositeRefEnabled is an encoder only option. It should not be stored in the SPS.
This commit is the last to remove unused parameters from SPSNext. Thus also
all comments related to SPSNext are removed.

Clean-up of 2 parts in the ISP code that are redundant. The changes do not alter the performance in any way, i.e., the results are exactly the same.

1) In the full RD intra mode tests loop (estIntraPredLumaQT) there is the following condition:
    if ( uiOrgMode <= DC_IDX ) -> do X; else-> do X.
Since X is the same in both cases, the redundant code has been removed.

2) In xRecurIntraCodingLumaQT there is the threshold definition

double threshold = nSubPartitions == 2 ? 0.95 : subTuCounter == 0 ? 0.67 : subTuCounter == 1 ? 0.83 : 0.91;

Since subTuCounter can never be 0 (it is at least 1) at the time this expression is evaluated, the code has been simplified in the following way:

double threshold = nSubPartitions == 2 ? 0.95 : subTuCounter == 1 ? 0.83 : 0.91;

AMVR (formely IMV) now has only one mode, which used to be mode #2
- remove SPS imv_mode parameter
- remove encoder configuration for mode #1 (mode #2 replaces mode #1)
- adapt config files to refer tp mode #1
- rename SPS syntax elements and access functions to AMVR

Note: IMV to AMVR renaming in other parts of the software should be done by proponents.

When MC for luma only is desired, use existing luma/chroma parameters
instead of encoder-specific field in data structure

Also take care that luma only MC doesn't imply IBC

- The M0297 zero-out is also supported for SBT now.
- The zero-out scanning code is moved out of residual_coding_subblock.

Deleted the TU retrieval from the DQP code in xCompressCU and the TU pointer being equal to nullptr check.