Retrospective commit from 2009-09-19.

Retrospective commit from 2009-09-19.

Begin work on bidi initialization and other cleanup.
Remove all STANDALONE code from bidi.c.

 xdisp.c (init_iterator): Call bidi_init_it.  Set
 bidi_it->bytepos if buffer position specified.
 (reseat_1): Don't call bidi_init_it.  Call bidi_paragraph_init
 instead.  Move back to preceding character before the call to
 bidi_get_next_char_visually.
 bidi.c: Remove all STANDALONE parts.
 (bidi_init_it): Init bidi_it->charpos and bidi_it->bytepos to -1.
 Don't call bidi_paragraph_init.  Change arguments.
 (bidi_paragraph_init): Remove code for negative pos.
 dispextern.h <bidi_it>: Rename orig_type to type_after_w1 and
 pristine_type to orig_type.