bit-panel shouldn't use the title attribute

[marshallswain]

Using the title attribute on the bit-panel causes the browser to show a tooltip any time you hover over any part of the tab's contents. This can result in a very confusing UX when the name of the tab pops up completely out of context. Maybe we can have it check for a tab-title attribute if there's not a title and do a patch or minor release?

[justinbmeyer]

Sure, we could probably use a getter so it's backwards compat:

tabTitle: {
  get: function(lastSet){
    if(lastSet) return lastSet;
    return this.attr("title");
  }
}