Make device pairing more robust

[dmulcahey]

Improve the feedback mechanisms, retries, and handling of device joins. We should provide a similar level of information during device joins that we provide during device reconfiguration.

How should we handle devices that pair but don't complete configuration successfully?
How many retries should be attempted (if any)?
Should we automatically kick devices that fail for any reason? (this could get tricky if we can't communicate with the device)