Replaced some opengl fixed functions with shaders. Temporary ShyotlUseLegacyRenderPath setting to debug if this change actually improves framerate at all (setting not tied to callbacks. Have to toggle shaders to have stuff pick up the setting change)

indra/llrender/llimagegl.cpp

@@ -1400,6 +1400,8 @@ BOOL LLImageGL::readBackRaw(S32 discard_level, LLImageRaw* imageraw, bool compre
 
 void LLImageGL::deleteDeadTextures()
 {
+	bool reset = false;
+
 	while (!sDeadTextureList.empty())
 	{
 		GLuint tex = sDeadTextureList.front();
@@ -1412,12 +1414,22 @@ void LLImageGL::deleteDeadTextures()
 			{
 				tex_unit->unbind(tex_unit->getCurrType());
 				stop_glerror();
+
+				if (i > 0)
+				{
+					reset = true;
+				}
 			}
 		}
 		
 		glDeleteTextures(1, &tex);
 		stop_glerror();
 	}
+
+	if (reset)
+	{
+		gGL.getTexUnit(0)->activate();
+	}
 }
 		
 void LLImageGL::destroyGLTexture()