Move robots.txt out of static

Stage 1 of allowing dynamic robots.txt based
on subdomain, so we can disallow on non-www.
Disallow crawlers except on www.(g.domain)
Remove old restriction on msnbot
Fix 'Disallow:' clause
Redirect /s/ to /submit or /tb/

Much code removed, as we no longer need to
handle /s/ generating toolbar views
Remove one layer of redirection from /:urloid
minor import cleanup in toolbar.py
Fix unicode issue in /s/ redirect