Interface tweaks, partly thanks to ADoS

- Bottom buttons now have standardized size of 38x38 (one pixel larger than before in both dimensions)
- Padding in terrain screen is now uniform
- Bottom button help pages now match the actual toolbars
- Bottom buttons are now specified in a flexible way which would allow for easily reordering them or making a new mode toolbar

src/boe.graphics.hpp

@@ -28,7 +28,7 @@ void draw_startup(short but_type);
 void draw_anim();
 void place_anim(); 
 void draw_start_button(short which_position,short which_button);
-void main_button_click(rectangle button_rect);
+void main_button_click(int which_button);
 void arrow_button_click(rectangle button_rect);
 void end_startup();
 void Set_up_win ();