Cursors on MS Windows

[Germán Arias]

After some days trying to solve the cursor problems on Windows, I found
a solution that, I think, is better than the corresponding solution in
TestPlant branch. Initially I tried to implement the TestPlant solution,
but this have problems (as you can see in the comments in that branch).
So I worked in my own solution, but this (like the TestPlant solution)
requires a small change in the side of GUI. We need know the count of
cursors in gnustep_gui_cursor_stack, to remove our cursors when the
mouse enter an area which is drawed by Windows (a menu or a nonclient
area). But the variable "gnustep_gui_cursor_stack" is not accessible
outside of NSCursor. So, could I add something like this at NSCursor?:

#ifdef WIN32
+ (NSUInteger) count
{
  return [gnustep_gui_cursor_stack count];
}
#endif

Germán