Use bool for boolean in xdisp.c

Use bool for boolean in xdisp.c

* dispextern.h (display_prop_intangible_p, resize_mini_window)
(pixel_to_glyph_coords, mark_window_display_accurate)
(compute_display_string_pos, handle_tool_bar_click)
(x_intersect_rectangles, clear_mouse_face, display_tty_menu_item):
* lisp.h (setup_echo_area_for_printing, message_with_string)
(pos_visible_p): Use bool for boolean.
* xdisp.c: Use bool, true, false intstead of int, 1, 0.
Remove unnecessary forward decls.
(trace_move) [DEBUG_TRACE_MOVE]: Now static.
(CHECK_IT, CHECK_WINDOW_END):
Now an inline function that is always defined.
(check_it) [0]:
(check_window_end) [oGLYPH_DEBUG && ENABLE_CHECKING]:
Remove; no longer needed.
(handle_stop): Prefer (X && !Y) to (X ? !Y : 0).
(get_overlay_strings): Omit unnecessary casts.
(forward_to_next_line_start):
(Ftool_bar_height):
Prefer !BOOL to (BOOL ? 0 : 1).
(next_element_function): New typedef.
(get_next_element): Use it.  Now const.
(IT_POS_VALID_AFTER_MOVE_P): Prefer !X || Y==0 to (X ? Y==0 : 1).
(vmessage): Now ATTRIBUTE_FORMAT_PRINTF (1, 0), to pacify GCC 4.9.2
(display_echo_area): Prefer BOOLEXPR to BOOLEXPR ? 1 : 0.
(tool_bar_item_info): Simplify.
(invisible_prop): Rename from invisible_p, since it doesn't
return bool.  All callers changed.
(x_produce_glyphs): Simplify.