More fixes for mouse glyph calculations (Bug#16647).

More fixes for mouse glyph calculations (Bug#16647).

More fixes for mouse glyph calculations (Bug#16647).
* window.c (coordinates_in_window): In intersection of
horizontal and vertical window dividers prefer the horizontal
one.  Add some extra parens to last fix.
(window_relative_x_coord): Return x-coordinate for header and
mode line too.
* xdisp.c (remember_mouse_glyph): In text area don't extend
glyph into mode line to show the vertical drag cursor there
immediately.  Subdivide mouse glyphs in right fringes to show a
horizontal drag cursor as soon as we enter the "grabbable width"
portion.  Handle vertical border case separately.  Do not
subdivide window divider areas.
(note_mouse_highlight): On bottom divider of bottommost windows
show vertical drag cursor only when the minibuffer window can be
resized.