Fix use with md-virtual-repeat (and other directives that recycle rep…

[jayellsbrg]

…eated items): update self.id before each access.

Since md-virtual-repeat recycles elements, the model will update, but not create a new element, so postLink, and consequently, reassignment of self.id, would not run again.

• Also remove use of $parse. The model and items that are being accessed have already been parsed, but more importantly, md-virtual-repeat scrolling lagged/froze up when running the parse function every time.