Add some new members to window structure in window.h.

Add some new members to window structure in window.h.

* window.h (window): Add some new members to window structure -
normal_lines, normal_cols, new_total, new_normal, clone_number,
splits, nest, prev_buffers, next_buffers.
(WINDOW_TOTAL_SIZE): Move here from window.c.
(MIN_SAFE_WINDOW_WIDTH, MIN_SAFE_WINDOW_HEIGHT): Define.

* window.c (WINDOW_TOTAL_SIZE): Move to window.h.
(make_dummy_parent): Set new members of windows structure.
(make_window): Move down in code.  Handle new members of window
structure.
(Fwindow_clone_number, Fwindow_splits, Fset_window_splits)
(Fwindow_nest, Fset_window_nest, Fwindow_new_total)
(Fwindow_normal_size, Fwindow_new_normal, Fwindow_prev_buffers)
(Fset_window_prev_buffers, Fwindow_next_buffers)
(Fset_window_next_buffers, Fset_window_clone_number): New
functions.
(Fwindow_hscroll, Fwindow_at, Fwindow_point, Fwindow_start)
(Fwindow_end, Fwindow_line_height, Fset_window_dedicated_p):
Doc-string fixes.
(Fwindow_parameters, Fwindow_parameter, Fset_window_parameter):
Argument WINDOW can be now internal window too.
(Fwindow_use_time): Move up in code.
(Fget_buffer_window): Rename argument FRAME to ALL-FRAMES.
Rewrite doc-string.
(Fset_window_configuration, saved_window)
(Fcurrent_window_configuration, save_window_save): Handle new
members of window structure.