Retrospective commit from 2009-08-22.

Retrospective commit from 2009-08-22.

Staticpro bidi_char_table, add type checking where bidi type is assigned.

 bidi.c (bidi_initialize): staticpro bidi_char_table.
 (bidi_check_type): New function.
 (bidi_cache_iterator_state, bidi_remember_char)
 (bidi_resolve_explicit_1, bidi_resolve_explicit)
 (bidi_resolve_weak, bidi_resolve_neutral)
 (bidi_level_of_next_char): Use it to validate the bidi type
 assigned to the iterator.