Allow fine-grained image-cache flushing.

Allow fine-grained image-cache flushing.
* dispextern.h (struct image): Add `dependencies' field.
(clear_image_caches): Change arg to Lisp_Object.
* image.c (make_image): Initialize `dependencies' field.
(clear_image_cache): Change arg to allow fine-grained flushing.
Perform the flush even if image-cache-eviction-delay is nil.
(clear_image_caches): Change arg to Lisp_Object.
(Fclear_image_cache): Expand meaning of the argument.
(mark_image): Mark `dependencies' field.
* xfaces.c (clear_face_cache): Adapt arg to call to clear_image_caches.
(lface_hash): Use XHASH rather than XFASTINT.
(face_at_buffer_position): Fix int -> EMACS_INT position.
* xdisp.c (next_overlay_change): Fix int -> EMACS_INT position.
(select_frame_for_redisplay): Remove code duplication.
(redisplay_internal): Adapt arg to call to clear_image_caches.