2D Rewrite Step [1]

-=-=-=-=-=-=-=-=-=-

-Moved drawing code to a single function that takes linked list (should make it easier to optimize in the future).
-Implemented Z ordering of 2D nodes. Node2D and those that inherit have a visibility/Z property that affects drawing order (besides the tree order)
-Removed OpenGL ES 1.x support. Good riddance!

platform/windows/os_windows.cpp

@@ -27,7 +27,7 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 #include "drivers/gles2/rasterizer_gles2.h"
-#include "drivers/gles1/rasterizer_gles1.h"
+
 #include "os_windows.h"
 #include "drivers/nedmalloc/memory_pool_static_nedmalloc.h"
 #include "drivers/unix/memory_pool_static_malloc.h"
@@ -130,11 +130,11 @@ void RedirectIOToConsole() {
 
 int OS_Windows::get_video_driver_count() const {
 
-	return 2;
+	return 1;
 }
 const char * OS_Windows::get_video_driver_name(int p_driver) const {
 
-	return p_driver==0?"GLES2":"GLES1";
+	return p_driver=="GLES2";
 }
 
 OS::VideoMode OS_Windows::get_default_video_mode() const {