Innitial commit of experimental v2 texture system port work. Compiles and runs on windows, at least. Fixing bugs as they come.

Need to test:
localassetbrowser
preview related floaters
hgfloatertexteditor
maps
media textures! Currently very hacky
web browser
alpha masks on avatars
bumpmaps
Are all sky components appearing?
LLViewerDynamicTexture (texture baking, browser, animated textures, anim previews, etc)
Snapshot related features
Customize avatar
vfs floater
UI textures in general
Texture priority issues

indra/llrender/llrender.h

@@ -51,6 +51,7 @@ class LLVertexBuffer;
 class LLCubeMap;
 class LLImageGL;
 class LLRenderTarget;
+class LLTexture ;
 
 class LLTexUnit
 {
@@ -149,6 +150,7 @@ public:
 	// Binds the LLImageGL to this texture unit 
 	// (automatically enables the unit for the LLImageGL's texture type)
 	bool bind(LLImageGL* texture, bool for_rendering = false, bool forceBind = false);
+	bool bind(LLTexture* texture, bool for_rendering = false, bool forceBind = false);
 
 	// Binds a cubemap to this texture unit 
 	// (automatically enables the texture unit for cubemaps)