SH-2244 Vertex buffer cleanup, fix for bad vertices in rigged attachments, added "RenderUseVAO" debug setting to control whether or not to use VAO's in non-core GL profiles.

SH-2244 Fix "RenderGLCoreProfile" actually make a core profile context and modify viewer to run under said context without generating errors.

SH-2244 Add "RenderGLCoreProfile" debug setting that allows the viewer to start with a non-compatibility-profile OpenGL context.

SH-2242 FXAA support instead of unreliable multisample textures (done here because it's a smaller change than integrating glVertexAttrib with FSAA pipe).  Shader integration with LLDynamicTexture subclasses.

SH-2181 Fix for alpha flickering when basic shaders enabled (don't use glAlphaFunc when shaders are available).

Reviewed by Leslie

EXP-1021 FIX Position of web content browser dictates position of profile panel - profile panel position changes do not persist
EXP-1030 FIX Search button toggle can get out of synch in bottom bar
made llinstancetracker::iterator do own nested level management (removing need for separate guard)
added support for filename= to floaters
can pass in arbitrary window_class to floaters

SH-2031 High risk changeset, but potentially high reward.  Addresses frame stalls in renderer by never using the fixed function pipeline if shaders are available.

SH-2038 Fix for some compiler errors from the apple tweaks -- also add a fence API (disabled for now).

SH-1682 Use GL_ARB_map_buffer_range to mitigate impact of mapping larger vertex buffer objects.  Limit number of textures per batch to 6 (prevents frame stalls on NVIDIA).

SH-1682 Dynamically adjust the number of texture channels to use for indexed texture rendering based on available hardware.

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

* 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

SH-874 Followup -- use GL_NVX_gpu_memory_info for NVIDIA chips to detect actual installed and available VRAM.

SH-874 Properly detect available video memory on ATI cards and disable vertex buffer objects when available vram is under 256MB.

* Now called 'HeadlessClient' instead of 'DisableRendering'
* Removed most cases where we skipped certain behaviors in the client when in this mode.  This gets us closer to a 'true' client, for testing purposes.

SH-874 Revert much of the bad water bounding box and distortion texture usage changes from SNOW-643 and properly occlusion cull void water patches for machines without depth clamp.

originally done in http://bitbucket.org/leyla/leyla-mesh-development

Faster occlusion queries (take advantage of GL_ARB_occlusion_query2 where available and don't read back result if it will block).

A copy constructor was implemented which did a memcpy,
which included the vtable pointer which was to another object of another
class (same child though).  This resulted in the wrong destructor
being called.
The reason for the memcpy was for alignment purposes.

The solution was to move to LLVector4a, which is intrinsicly aligned.

Also, did some performance optimizations based on the LLVector4a optimizations.


The solution was to re-implement the

SH-373 Update glext.h, disable anti-aliasing on ATI when rendering deferred.  Get rid of RenderUseFBO debug setting (only use FBO when rendering deferred).  Use GL_ARB_framebuffer_objects instead of GL_EXT_...

No need to test because there are no negative effects.

Port of SNOW-643 : Water flicker at high altitude. This doesn't fix the low altitude flicker though (STORM-306)

back-out the back-out for this branch.  yay.

Backing out this merge that I pushed (prematurely) to the wrong place.

added more debug code for EXT-6791: [crashhunters] Intel 965 Crash in glCopyTexSubImage2D