Fix handling of window-min-height/-width (Bug#16738).

Fix handling of window-min-height/-width (Bug#16738).

* window.el (window--dump-window, window--dump-frame): New
functions.
(window--min-size-1): Account for window dividers.  When
window-resize-pixelwise is nil, delay rounding till after the
sum of the window components has been calculated.
(window--min-delta-1, window--max-delta-1): When PIXELWISE is
nil make sure at least one text line and two text columns remain
fully visible.
(window-resize): Signal an error when window-resize-apply fails.
(window--resize-child-windows): Fix calculation of by how many
pixels a window can still be shrunk via window-new-normal.
(adjust-window-trailing-edge): Call window--resizable with
correct TRAIL argument.