* w32term.c (w32_term_init): Don't initialize the image cache

* w32term.c (w32_term_init): Don't initialize the image cache
here; it will be done in init_frame_faces.

* xterm.h (struct xim_inst_t): Definition moved from xterm.c.
(struct x_display_info): Remove unused member null_pixel.  New
member xim_callback_data.

* xterm.c (struct xim_inst_t): Definition moved to xterm.h.
(xim_initialize): Save pointer to callback function data.
(xim_close_dpy): Free callback function data.  Call XCloseIM,
reverting 2008-11-04 change by David Smith.
(x_term_init): Don't initialize the image cache here; it will be
done in init_frame_faces.  Remove ancient "null_pixel" cruft.
(x_delete_display): Free x_dnd_atoms member.