Fixed comments in modals

Hi.

Today I had problems with an HTML-comment in my modal-template. So I added a function to choose the first element-node (`nodeType === 1`) of the modal-jqLite-collection instead of simply the first element at all. I made it a private function as I don't know if there are any other occurrences of this kind of problem in the Angular-Ionic-codebase.

Best regards
Emanuel