Implement scrollbars

- They work almost as you'd expect, though holding the mouse down on an arrow only scrolls once, and it's a little jerky
- Add an additional refresh option to redraw_screen, currently only partially implemented
- Scrollbars now have a page size in addition to pos and max
- cControl::handleClick() now takes the location clicked as a parameter, though the default implementation doesn't use it
- cControl::handleClick() is no longer responsible for redrawing the control when there is no parent dialog
- Fix cTextMsg not allowing retrieval of frame style

osx/boe.graphics.cpp

@@ -622,9 +622,11 @@ void redraw_screen(int refresh) {
 			draw_startup(0);
 			break;
 		case MODE_TALKING:
+			if(refresh & REFRESH_DLOG); // TODO: Should call place_talk_str, but we don't have the strings
 			refresh_talking();
 			break;
 		case MODE_SHOPPING:
+			if(refresh & REFRESH_DLOG) draw_shop_graphics(0,{0,0,0,0});
 			refresh_shopping();
 			break;
 		default: