md-chips checks for duplicates before md-on-append is called

[webley]

The appendChip function in chipsController.js does some duplicate-checking to prevent adding the same chip multiple times. Unfortunately, it checks for matches before md-on-append is called. If md-on-append converts a string input into an object, for instance, the duplicate checking will always fail.

Presumably it should either check for duplicates after md-on-append has been called, or keep a separate collection of unmodified chips to check against.

[hueyy]

+1