Remove confusing word "faculative" from comments

Reviewers: campbellbarton

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D711
Fix T41318: API change in OSL, I see no other cases but there might be
Fix for out of bounds write while dragging
OSX/cmake: allow for llvm dynamic builds too, but prefer static
OSX/clang: Fix T41123, crashing osl when optimization level > O0 is used for osl_shaders.cpp
Add some missng casts to the size_t
Correct Python exceptions

T35358 by Codemanx
Fix T41343, hard to remove group from objects.

Added a small menu with a few helper oerators next to each group panel:

* Remove group from all objects
* Select objects in group

More could be added possibly in the future.

Thanks to Campbell for the advice here.
Cleanup: mostly move together main area init/draw/handler callback, and some generic cleanup (tabs, comments...).
Fix T41323: Sequencer: video window taking all the place when switching to split view.

Issue is that, when we switch from full preview view to combined view, preview area has
its `sizey` set to use all available height, which leaves nothing for poor main area.

For now, make checks when switching mode to combined one, so that both areas have
resonable `sizey` values. Not perfect, but works.
UI: move button to set dupli-offset into group menu
Fix T41047: Text objects flipping
GHash/EdgeHash: avoid NULL check on iterator init
BMesh: use existing lookup tables when remapping
initial intersect code
initial isect
intersection script
test vert intersection
check for intersections where no new verts are added first
minor fixes