Now uses KEY_PAGEUP and KEY_PAGEDN, as defined by key_defs.js rather than...

Now uses KEY_PAGEUP and KEY_PAGEDN, as defined by key_defs.js rather than using its own pageup/pagedown variable definitions as it was doing before.  Also, fixed some weirdness & improved the apperance when selecting & de-selecting items in multi-select mode when using color arrays to color the items.