Fix for crash due to race condition when uploading meshes.

Trying again, this time adding SDK versions to GLOD's linker commands
as well as its compile command. Ugh.

Trying this again, attempting one more update to fix the issues of not
being able to run with GLOD on 10.5.

xcode didn't like the way we were defining inner classes and assuming that if the outer class
was a friend that the inner class would be too. Couldn't forward-declare the inner class
so had to re-arrange the order of class declaration.

Between re-ordering the class declarations, and explicitly making the inner class a friend,
this un-sticks the mac build, and makes it happy.

Code reviewed by davep.

Pushing in the cmake change that will make the mac build use the non-stub version of the convex decomp lib.

Reviewed by prep.

Extended the current filename checking to handle the case where we
have a user cancel a selection of an LOD file beyond the first.
mLoading is made false in either case, but the dialog is closed
if a file has not been chosen for the highest LOD.

Interface/state for rendering convex hull physics shapes.  Still need to implement gMeshRepo.buildHull

Correct rendering of prims as user meshes/analytical shapes when not set to convex hull or no physics.