SH-469 Don't use depth buffers and multisample buffers where not absolutely needed -- make sample counts consistent between shaders and render targets.

SH-810 FIXED Mesh uploader should enable Physics Analyze after "Use Level of Detail" is picked.

Both changes together in this changeset.

SH-712:Asset error given on upload of duck.dae using High LOD for physics shape - Analyze seems to not complete;
SH-889: Viewer crash when analyzing physics LOD;
SH-890: Viewer crash on Exit after analyzing physics layer which never seems to complete

* Fixed ATI mac "lighting and shadows" related crash
* Fixed up numerous GL errors on macs related to multiple color formats,
  the use of glEnable/glDisable on textures above the texture unit count
  and old ATI-specific code that was not appropriate for Mac.
* Disabled SSAO for ATI macs due to it not working with shadows
* Ongoing work to properly get shadows and SSAO functioning on ATI macs is required.

Reviewed by davep