Don't show challenge/PM buttons for yourself
There are various obscure situations where you might want to for
testing, so doing so isn't banned server-side, but it's banned client-
side where it's more likely to be a misclick than anything else.
Fix battle.css link
Support playing in battles
Absolute URIs to avoid unnecessary 301 redirects
Merge .htaccess with `master` branch
Closing PM window cancels challenge