Undo 2005-10-23 change.

Undo 2005-10-23 change.
(last_mouse_glyph_frame): New var.
(note_mouse_movement): Say mouse moved if current frame differs
from last_mouse_glyph_frame, and update last_mouse_glyph_frame.
(XTmouse_position): Set last_mouse_glyph_frame.
(handle_one_xevent): Clear last_mouse_glyph_frame [instead of
last_mouse_glyph] on mouse up/down event.