Clean up mitigation code

[tomorgan]

Lync's GetContactInformation() call returns syncronously, but isn't always ready immediatly, leading to us either getting data in a state where it's not yet ready, or getting a NotReadyException.

I'm mitigating this with some nast while loops and thread sleeps, but I don't like it. Raising it as an issue to sort out later - there must be a better way of doing this.

[tomorgan]

done - refactored to use notification events.