move render to systems

ui/mainwindow/viewport.go

@@ -11,7 +11,7 @@ type ViewPort struct {
 	CameraCoords types.Coords
 }
 
-func NewViewPort(x, y, w, h int, layer *Layer) *ViewPort {
+func NewViewPort(x, y, w, h int) *ViewPort {
 	vp := ViewPort{
 		Rect:  types.Rect{x, y, w, h},
 	}