Lowercase oTransitionEnd; fix gh-pages for Opera

Bootstrap had an old bug in it (fixed in latest version), where it had `oTransitionEnd` as the transition event name--unless it is `otransitionend` it won't work with jQuery.

Compare: 

http://miketaylr.github.com/Font-Awesome/#icon/icon-envelope-alt with http://fortawesome.github.com/Font-Awesome/#icon/icon-envelope-alt

The  lightbox fails w/o this fix.

Cheers.