Another wps rework:

Another wps rework:
*rename gui_wps_refresh() to gui_wps_redraw() and update() to gui_wps_update() to better describe what they do
*Clear things up and differentiate better between gui_wps_redraw()/gui_wps_display()/gui_wps_update() (it wasn't so what they're supposed to do before)
*cleanup gui_wps_display() and gui_wps_update() quite a bit
*Remove unused/unneeded code, do some pointer copying to save binsize, and code cleanup at several places

Visible changes should be small

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20483 a1c6a512-1295-4272-9138-f99709370657