(Ffontset_info, check_fontset_name): New arg frame.

(Ffontset_info, check_fontset_name): New arg frame.
Hanlde NAME nil and t correctly.  Callers changed.
(font_def_arg, add_arg, from_arg, to_arg): Delete them.
(set_fontset_font): Change ARG to a vector.  Handle range_list in
ARG correctly.
(Fset_fontset_font): Fix the case that TARGET is both a script
name and charset name.  Adjusted the arg to set_fontset_font for
the above change.
(fontset_from_font): Fix previous change.
(Ffontset_info): Adjusted for the 2008-07-09 change of fontset
entry.  If FONTSET is the default fontset, don't set the extra
slot of the returning char-table.