Some more fixes following pixelwise resize changes including one for Bug#16306.

Some more fixes following pixelwise resize changes including one for Bug#16306.

* gtkutil.c (x_wm_set_size_hint): Have size hints respect value
of frame_resize_pixelwise.
* widget.c (pixel_to_text_size): New function.
(update_wm_hints): Have size hints respect value of
frame_resize_pixelwise.
(EmacsFrameResize): Alway process resize requests pixelwise.
* window.c (grow_mini_window): Make sure mini window is at least
one line tall.
* xdisp.c (display_menu_bar): Make sure menubar extends till
right end of frame.
* xfns.c (x_set_menu_bar_lines): Resize frame windows pixelwise.
(x_set_tool_bar_lines): Calculate pixelwise.
* xterm.c (x_wm_set_size_hint): Have size hints respect value of
frame_resize_pixelwise.