Add RNA access to packed libraries
Fix T41062: "copy to selected" doens't work for all attributes.

The issue was that some properties are no direct children of the struct we support in 'copy to selected'
(RNA_Sequence in this case). Since we can't use the ID of sequences here (it's the scene, while we need
a sequence level of control), we had to add a new API helper to RNA path, which takes a RNA type
and return a path relative to the closest ancester of that type.

This way, we get a path from the RNA_Sequence, and can easily apply it to all other valid sequences
to copy the property.

Review, suggestions and edits by Campbell Barton, thanks!
OSX/cmake: force LLVM_STATIC ON, to fix linking issues
OSX/cmake: move last commited line to a better place
Correct change to dupli-drawing

Need exceptions so dupli-frames objects draw in render-only mode.
Spelling
Remove SVN references
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