changed FindBindings to use Regex

With Angular 1.3 trying to find a binding in the following format seemed to break:
    
    <span>{{ myBinding }}</span>

The data looks like this:
    angular.element(bindings[i]).data().$binding = [ " myBinding " ];

By switching to a RegExp, it basically does the indexOf test that was done before, but it seems to process on arrays as well (which looks to match the behavior in the main protractor repo).