Blender Git Loki

Undo: replace global access w/ ED_undo_stack_get

While I'd like to avoid using this too much since the operator
system should handle.
It's less trouble than accessing it inline each time.

PyAPI: Add PyC_Tuple_Pack_F64 utility

Build: add WITH_OPENVDB_3_ABI_COMPATIBLE option.

Better fix for T54457. It seems Debian compiles OpenVDB without ABI 3
compatibility, while Arch does enable it as is the default in the OpeVDB
CMake build system.

So now there's an option that the distribution can set depending on how
they compile their OpenVDB package.

Cleanup: remove redundant imbuf return values

Some functions always returned the input argument
which was never used.

This made code read as if there might be a leak.

Now return a boolean (true the imbuf is modified).

Build: fixes for the Intel compiler versions 2016, 2017, 2018.

Differential Revision: https://developer.blender.org/D3109

Cleanup: newlines left in messages

Cleanup: move undo into it's own directory

Split out undo API from ED_util.h into ED_undo.h

Cleanup: move BKE_global include under ifdef's

Undo: store active curve shape key in edit-mode

Logging: use for Python API

Adds categories "bpy.context" & "bpy.rna"

imbuf: revert some of the changes of rBb6ba3c682dd6615e760905572a5bcd69bb46371f since they broke the build.

Fix compiling with Alembic

Still need G.main

Correct accidental changes by C Logging addition

Error in 891c1cfc9a3

Resolve unsigned comparison error w/ MSVC

Cleanup: remove global header

Cleanup: warning

Removed by accident in last commit

Undo: unified undo system w/ linear history

- Use a single undo history for all operations.
- UndoType's are registered and poll the context to check if they
should be used when performing an undo push.
- Mode switching is used to ensure the state is correct before
undo data is restored.
- Some undo types accumulate changes (image & text editing)
others store the state multiple times (with de-duplication).
This is supported by checking UndoStack.mode `ACCUMULATE` / `STORE`.
- Each undo step stores ID datablocks they use with utilities to help
manage restoring correct ID's.
Needed since global undo is now mixed with other modes undo.
- Currently performs each undo step when going up/down history
Previously this wasn't done, making history fail in some cases.
This can be optimized to skip some combinations of undo steps.

grease-pencil is an exception which has not been updated
since it integrates undo into the draw-session.

See D3113

BLI_sort_utils: add pointer sorting callback

Also rename Pointer -> Ptr

Logging: fix own error with formatting