design and implement miner pairing mechanism

[tjwebb]

Before a Miner is adopted by a User, the User should have to set a certain worker name in cgminer or something to prove that they own the miner.

[tjwebb]

cc @smcki012 a security feature that I forgot to mention. cgminer allows IP-based access restrictions (e.g., only allow hashpanel server access), but another good measure would be to implement a "pairing" system where you have to prove that you have independent access to the miner.