New BSIP: Market Making Reward Pool

Daniel "bytemaster" Larimer proposed a mechanism to subsidize market liquidity in Feb. 2016 (link at the end). Due to historical reasons, it didn't get implemented on BitShares. Lately it got implemented on Steem and got disabled after being active for 25 days (https://github.com/steemit/steem/commit/5cb8019b5804fa0f659d88cffe2ad4cafafd981d). While the mechanism did lead to amazing market liquidity, the measurement of contributions to liquidity and the rewarding settings were debatable. Nevertheless, the idea about reward pools was good.

As of writing, there is a market making contest for the BitShares DEX in planning (link at the end). If the result is positive, it's good to implement it into the protocol.

* Any user *or* worker can contribute funds to the reward pool. These funds can be denominated in any asset specified by the asset owner.
* The asset owner has the ability to enable this feature for any market their asset trades in and to specify the asset used to fund the reward pool.
* (details about contribution measurement and rewarding will be added here later)

Links:
* The ongoing market making contest https://bitsharestalk.org/index.php?topic=31515.0
* Old discussion "Subsidizing Market Liquidity" https://bitsharestalk.org/index.php/topic,21544.0.html

Start with the ongoing market making contest and the old “Subsidizing Market Liquidity” discussion linked in the issue, then review the Steem commit for the prior implementation. The issue is not ready for coding: contribution measurement, reward settings, market scope, and protocol entry points must be specified before completion can be defined.

Written by the indexing model from the issue text.