COMP Distribution System

This is the final release for the COMP distribution mechanism to the Comptroller. It contains the deployment configurations for mainnet, kovan, and ropsten, as well as the code changes for the protocol.

Once applied, users of 'comped' markets will receive units of the Compound governance token whenever they interact with the protocol. COMP is distributed at a steady rate (controlled by the admin), and earned based on the fraction of total supply or borrow held by each user within a market, and that market's share of total interest generated. Above a certain threshold, earned COMP is automatically transferred to the user. COMP which has not yet been transferred may be claimed explicitly.

This patch also adds a Reservoir contract, which will drip COMP to the Comptroller contract at a constant rate, whenever poked. The Reservoir effectively guarantees the Comptroller will have enough COMP to distribute, up to a maximum rate.

The Comptroller also now tracks the entire list of markets that have ever been supported. The existing Market struct is modified to track an additional 'isComped' field.