Make core/ includes absolute, remove subfolders from include path

This allows more consistency in the manner we include core headers,
where previously there would be a mix of absolute, relative and
include path-dependent includes.

drivers/gles2/rasterizer_scene_gles2.cpp

@@ -27,16 +27,17 @@
 /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
+
 #include "rasterizer_scene_gles2.h"
-#include "math/transform.h"
-#include "math_funcs.h"
-#include "os/os.h"
-#include "project_settings.h"
+
+#include "core/math/math_funcs.h"
+#include "core/math/transform.h"
+#include "core/os/os.h"
+#include "core/project_settings.h"
+#include "core/vmap.h"
 #include "rasterizer_canvas_gles2.h"
 #include "servers/visual/visual_server_raster.h"
 
-#include "vmap.h"
-
 #ifndef GLES_OVER_GL
 #define glClearDepth glClearDepthf
 #endif