- removes old getIBCMode functions from SPSNext
- fixes references to this function in
  * reshaper
  * hash based ME

Note: SPSNext is going to be removed. Fixes can also be applied with the removal patch.

Clean up scan data arrays

See merge request jvet/VVCSoftware_VTM!257

Fix spaces and indentation in CabacReader

See merge request !259

Remove outdated macros and associated code

See merge request !258

Remove JEM_USE_INTRA_BOUNDARY and HEVC_USE_4x4_DSTVII

Use a single array with elements that comprise scan x position, y
position, and index into block instead of separate arrays.

Simplify array initialization code

Align ALF trace with specification

See merge request !255

Cleanup CABAC contexts

See merge request !253

Remove unused variables / declarations

See merge request !254

Remove unused contexts and split intra mode contexts into luma and
chroma sets to align with text description

Update the software documentation/manual for VTM/JVET

See merge request jvet/VVCSoftware_VTM!252

- change README.txt to markdown (displays in GitLab)
- update build instructions
- update LaTEX document template for JVET and include it
- general updates for the software manual (authors, purpose, etc.)
- update build instructions (aligned with README)
- use code highlighting (requires Pygments installation)
- minor formatting updates

[Cosmetics] Cleanup trailing spaces

See merge request !240

Fixed the bugs of Ticket #169 in IntraPrediction.cpp

See merge request jvet/VVCSoftware_VTM!251

fix for issue #171 (negative shift)

See merge request !250

calculate and check shifts only when they are actually used

Cleanup: Remove unnecessary code/processing for MTS zero-out in DepQuant

See merge request !248

Fix: Prevents usage of wrong contexts in DepQuant

See merge request !247

M0421 aligned with proposed draft text (btDepth -> mttDepth), issue #170

See merge request jvet/VVCSoftware_VTM!246

The integration of JVET_M0297_32PT_MTS_ZERO_OUT adds unnecessary code as
well as unnecessary processing in the encoder quantization process. -
The suggested change simplifies the code and avoids unnecessary
processing for the zero-out region.

The suggested changes fix the following two issues:

[1]
For blocks with width>32 or height>32, the scan created in initRom()
(file Rom.cpp) are only valid for the non-zero-out region. However, in
Rom::xInitScanArrays() (file DepQuant.cpp), the zero-out region is also
used. This has the effect that the array raster2id[] contains wrong
values. As a consequence, wrong neighboring positions cpos[] are derived.

Even though a previous fix (fix #161) ensures that the positions are
clipped to a value inside the subblock, these positions could still be
wrong. It is suggested to fix the issue by correctly considering the
zero-out regions for larger blocks (which is the actual source of the problem).

[2]
In State::updateStateEOS(..), the array m_absLevelAndCtxInit should be
set equal to zero if a skipped subblock is selected. Otherwise, it could
be possible lead to a usage of wrongs contexts for following transform
coefficients.

In Rom::xInitScanArrays()

Fix ticket#166 on the context derivation of IBC flag

See merge request jvet/VVCSoftware_VTM!245

Minor code improvement on JVET_M0055_DEBUG_CTU

See merge request !244

JVET-M0055 DebugCTU and bug fix for #163

See merge request jvet/VVCSoftware_VTM!193

Jenkins CI: fix build rules

See merge request !243

change new build rule to be specific for Linux-build only
use usual parameters for enabling trace

Fix #155: Don't set GBiIdx too early

See merge request jvet/VVCSoftware_VTM!239

Adapt the fix for uninitialized memory access with REUSE_CU_RESULTS

See merge request !236

Fix decoder analyser

See merge request !242