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.text.cpp

@@ -549,6 +549,7 @@ void set_stat_window(short new_stat)
 	stat_window = new_stat;
 	if ((stat_window < 6) && (univ.party[stat_window].main_status != 1))
 		stat_window = first_active_pc();
+	item_sbar->setPageSize(8);
 	switch (stat_window) {
 		case 6:
 			for (i = 0; i < 60; i++)
@@ -563,6 +564,7 @@ void set_stat_window(short new_stat)
 			break;
 		case 7:
 			item_sbar->setMaximum(2);
+			item_sbar->setPageSize(2);
 			break;
 		default:
 			item_sbar->setMaximum(16);