Use threaded cost function and jacobian computation
Also made it theraded linear solver, seems it makes
sense for iterative schur with inner iterations
enabled.

Use OpenMO's max therads called from bundler code
to detect how many threads to use. Could be changed
in a way that number of threads is passing in options
from blender side in the future.

Also removed redundant V3D definition from compiler's
flags.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54886 954f8c5b-7b00-dc11-b283-0030488c597c
Dependency Graph: refactoring to move private functions to the private header,
and add more documentation about the public functions. Also removed unused graph
traversal code and other minor unused functions.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54887 954f8c5b-7b00-dc11-b283-0030488c597c
Add: [#34443] Ability to set 'Pivot Center for rotation/scale' missing in weight paint mode

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54888 954f8c5b-7b00-dc11-b283-0030488c597c