(x_figure_window_size): Handle `-' for top or left.

(x_figure_window_size): Handle `-' for top or left.
(Fx_parse_geometry): Handle one element at a time.
Give `-' when appropriate.
(x_figure_window_size): Allow just height or just width.

(Fx_create_frame): Use XNegative and YNegative to set win_gravity.
[USE_X_TOOLKIT] (x_window): Use XNegative and YNegative
to set win_gravity.  Pass new arg to x_calc_absolute_position.