New internal function returning a good step value for the mouse wheel. For

New internal function returning a good step value for the mouse wheel. For

Sun Feb 29 19:04:33 2004  Soeren Sandmann  <sandmann@daimi.au.dk>

	* gtk/gtkrange.c (_gtk_range_get_wheel_delta): New internal
	function returning a good step value for the mouse wheel. For
	scrollbars, base the step on page_size^(2/3), for other ranges,
	use 2 * step_increment.

	* gtk/gtkrange.c (gtk_range_scroll_event): Use it here ...

	* gtk/gtkscrolledwindow.c (gtk_scrolled_window_scroll_event):
	... and here.

	* gtk/gtkmenu.c (gtk_menu_leave_notify): Fix a warning.