Clear entire buffer to ensure all values in the buffer are valid
even though some values may lie outside the subset of coefficients
that is effectively coded

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.

patch from issue191 (without macro)

Fix ticket #153 on using uninitialized interDir and GBI array when MaxNumMergeCand=1 and MMVD uses the second merge candidate as base MV.

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.

Started failing after merging !294

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.

  - Sub-PU TMVP can generate an invalid inter candidate.
  - Simplify previous solution and eliminate duplicated code.

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

  - Fix overflow during reconstruction process.

- 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.

  - Sub-PU TMVP can generate an invalid inter candidate.