image: Combine clamp_view() and center_view ()
image: Combine clamp_view() and center_view ()

We need to clamp or center on a per axis basis.  If the window is wider
but the image is taller, we need to center horizontally but
clamp vertically.  We can only do that if by combining the two
functions.

sir-murray/weston,Fantu/compositor-spice,Gnurou/weston,giucam/weston,eyolfson/weston,jonnylamb/weston,udoprog/weston,Gnurou/weston,Tarnyko/weston-xdg_surface_present,Fantu/compositor-spice,xorgy/weston,kwm81/weston,kwm81/weston,eyolfson/weston,mchalupa/weston,Fantu/compositor-spice,krezovic/weston,udoprog/weston,Tarnyko/weston-xdg_surface_present,krezovic/weston,jonnylamb/weston,mchalupa/weston,sir-murray/weston,giucam/weston,xorgy/weston