Provide missing OpenGL ES 1.x extension for implementation read format/type.

src/OpenGL/libGLES_CM/Context.cpp

@@ -1082,13 +1082,13 @@ bool Context::getIntegerv(GLenum pname, GLint *params)
             }
         }
         break;
-    case GL_IMPLEMENTATION_COLOR_READ_TYPE:
+    case GL_IMPLEMENTATION_COLOR_READ_TYPE_OES:
 		{
 			Framebuffer *framebuffer = getFramebuffer();
 			*params = framebuffer->getImplementationColorReadType();
 		}
 		break;
-    case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
+    case GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES:
 		{
 			Framebuffer *framebuffer = getFramebuffer();
 			*params = framebuffer->getImplementationColorReadFormat();

src/OpenGL/libGLES_CM/libGLES_CM.cpp

@@ -2409,6 +2409,7 @@ const GLubyte* GL_APIENTRY glGetString(GLenum name)
 			"GL_OES_element_index_uint "
 			"GL_OES_framebuffer_object "
 			"GL_OES_packed_depth_stencil "
+			"GL_OES_read_format "
 			"GL_OES_rgb8_rgba8 "
 			"GL_OES_stencil8 "
 			"GL_OES_stencil_wrap "