Include "character.h" instead of "charset.h".

Include "character.h" instead of "charset.h".
(load_face_font): Adjusted for the change of choose_face_font and
FS_LOAD_FONT.
(generate_ascii_font): New function.
(set_lface_from_font_name): Adjusted for the change of
FS_LOAD_FONT.
(set_font_frame_param): Adjusted for the change of
choose_face_font.
(free_realized_face): Make it public.
(free_realized_faces_for_fontset): Renamed from
free_realized_multibyte_face.  Free also faces realized for ASCII.
(choose_face_font): Argments changed.  Adjusted for the change of
fontset_font_pattern and FS_LOAD_FONT.