add ng-focus and ng-blur to our vendored angular

allows setting searchActive on blur of the friends search input. without this,
mouse-entering and then clicking inside the search input sets searchActive to
true, hiding the friend counts, but without inputting a search query,
mouse-leaving it sets searchActive to false, showing the friend counts, even
though the search input is still expanded and focused.

cherry picks part of angular/angular.js@2bb27d4
more improvements around friending limits

allow using the select2 add friend widget when remainingFriendingQuota is 0,
but only for friends who are freeToFriend. improvements to tooltips and other
messaging around friend limits.