Move a bunch of math to cpp files + small fixes

src/math/Rect.cpp

@@ -0,0 +1,17 @@
+#include "common.h"
+
+CRect::CRect(void)
+{
+	left = 1000000.0f;
+	top = 1000000.0f;
+	right = -1000000.0f;
+	bottom = -1000000.0f;
+}
+
+CRect::CRect(float l, float t, float r, float b)
+{
+	left = l;
+	top = t;
+	right = r;
+	bottom = b;
+}