More precise control over values of some buffer-local variables.

More precise control over values of some buffer-local variables.
* keyboard.c (Qvertical_scroll_bar):
* frame.c (Qleft, Qright): Move to ...
* buffer.c (Qleft, Qright, Qvertical_scroll_bar): ... here.
* buffer.c (Qchoice, Qrange, Qoverwrite_mode, Qfraction): New symbols.
(syms_of_buffer): DEFSYM all of the above, attach special properties.
Use special symbols to DEFVAR_PER_BUFFER overwrite-mode,
vertical-scroll-bar, scroll-up-aggressively
and scroll-down-aggressively.
* buffer.h (Qchoice, Qrange, Qleft, Qright, Qvertical_scroll_bar):
Add declarations.
* nsfns.m, frame.h (Qleft, Qright):
* nsterm.m (Qleft): Remove declarations.
* gtkutil.c (toplevel): Include buffer.h.
* data.c (wrong_choice, wrong_range): New functions.
(store_symval_forwarding): Handle special properties of buffer-local
variables and use functions from the above to signal error, if any.