Added rect draw api

Added some new maths types
Updated shaders to use new D_Rect structure
Added rect buffers to frames
Misc cleanup

code/core/impl/math.c

@@ -1,3 +1,23 @@
+V2f V2F(F32 x, F32 y) {
+	V2f result = { x, y };
+	return result;
+}
+
+V3f V3F(F32 x, F32 y, F32 z) {
+	V3f result = { x, y, z };
+	return result;
+}
+
+V4f V4F(F32 x, F32 y, F32 z, F32 w) {
+	V4f result = { x, y, z, w };
+	return result;
+}
+
+R2f R2F(V2f min, V2f max) {
+	R2f result = { min, max };
+	return result;
+}
+
 V3f V3f_Neg(V3f x) {
 	V3f result = { -x.x, -x.y, -x.z };
 	return result;