bug#9209: bidi slowdown

[emacs user]

when using vm, I still see significant slowdowns in cursor motion in
the vm-summary buffer when bidi is on.  this is with a 3000+ lines
long buffer with the summary of the messages in the inbox.  please let
me know if there is any additional information I can provide.

2011-07-22  Eli Zaretskii

        Fix a significant slow-down of cursor motion with C-n, C-p,
        C-f/C-b, and C-v/M-v that couldn't keep up with keyboard
        auto-repeat under bidi redisplay in fontified buffers.

2011-07-28  Eli Zaretskii

        * buffer.c (init_buffer_once): Set bidi-display-reordering to t by
        default.

In GNU Emacs 24.0.50.1 (i386-apple-darwin11.0.0, NS apple-appkit-1138.00)
 of 2011-07-29 on dhcp-10-249-70-250.xx.edu
Windowing system distributor `Apple', version 10.3.1138
configured using `configure  '--with-ns' '--without-x''