add simple math containers

math/math.go

@@ -0,0 +1,18 @@
+package math
+
+type Vec2i struct {
+	X int
+	Y int
+}
+
+type Vec2f struct {
+	X float32
+	Y float32
+}
+
+type Rect4i struct {
+	X int
+	Y int
+	W int
+	H int
+}