comment-based repeater

- tests with jQuery currently failing (I'm working on that)
- IE drops any comments inside of `<select>` element, so there is no way to get it working there
- inside of the compile fn of the repeater directive there is no way to tell what the original node looked like, because it has been already replaced with a comment node at that point by transclusion, so I had to tack on a `$$originalNodeType` property on the linking fn that is built by the transclusion. I'm happy to consider other options if someone suggests some.