_NET_WM_STATE_MAXIMIZED_VERT
_NET_WM_STATE_MAXIMIZED_HORZ
A window is maximized if both _NET_WM_STATE_MAXIMIZED_VERT and
_NET_WM_STATE_MAXIMIZED_HORZ are set.
behaviors caused by some unusual operations. E.g., after entered
fullscreen, applications change windows to other states instead of
leaving fullscreen.
* maximization (also partially fixes strange Firefox behaviour)
* sane initial window placement
Firefox is stranger than most; it appears to maximize to double
X Screen width even on single head displays. Fixed (on multihead).
Mostly this is adding appropriate #includes and declarations,
but for WmImage.c we also change from using the proper name
for XmeGetMask, rather than the identical but renamed
version _DtGetMask which is not exported in any header.