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

Include "character.h" instead of "charset.h".
(copy_sub_char_table): Moved to chartab.c.
(Fcopy_sequence): Call copy_char_table for a char table.
(concat): Delete codes calling count_multibyte.
(string_char_to_byte): Adjusted for the new multibyte form.
(string_byte_to_char): Likewise.
(internal_equal): Adjusted for the change of char table structure.
(Fchar_table_subtype, Fchar_table_parent, Fset_char_table_parent,
Fchar_table_extra_slot, Fset_char_table_extra_slot,
Fchar_table_range, Fset_char_table_range, Fset_char_table_default,
char_table_translate, optimize_sub_char_table,
Foptimize_char_table, map_char_table, Fmap_char_table): Moved to
chartab.c.
(char_table_ref_and_index): Deleted.
(HASH_KEY, HASH_VALUE): Moved to lisp.h.
(Fmd5): Call preferred_coding_system instead of accessing
Vcoding_category_list.  Adjusted for the new code-conversion API.
(syms_of_fns): Defsubr for char table related functions moved to
chartab.c.