(IT_OVERFLOW_NEWLINE_INTO_FRINGE): Turn it off if word-wrapping.

(IT_OVERFLOW_NEWLINE_INTO_FRINGE): Turn it off if word-wrapping.
(IT_DISPLAYING_WHITESPACE): New macro.
(move_it_in_display_line_to): Handle MOVE_TO_X requests properly
when word-wrapping.  Simplify word-wrapping logic.  Use correct
pixel positions when saving copies of the iterator.
(display_line): Use proper wrap point if the last character on a
line was preceded by whitespace.