User:Gmaxwell/utxo spring cleaning

A brief plan to improve the state of the UTXO

• relay policy adjustments to may very tiny notification payments unattractive
• OP_RETURN exclusion from UTXO set (almost done)
• Coin control (almost done)
• free transaction policy biasing priority in favor of txn that reduce utxo set size
• wallet fragmentation visualization tool
• Adjust coin selection to attempt to spend whole privacy groups, subject to transaction size limits and some change size targeting.
  • Requires making the address grouping stuff more computationally efficient.
• Functionality to aid people in automatically 'giving away' configurable very small payments, e.g. you set it so that if you receive a payment less than 0.00001 you'll author a OP_RETURN,0 output ANYONE_CAN_PAY|NONE transaction and broadcast it. Many of these can be merged to give away this dust to miners.
• Mining logic to merge up ANYONE_CAN_PAY|NONE transactions
• UTXO cleaning contest: Get money from BTC foundation (and perhaps other interested parties), every UTXO destroyed (perhaps only those submitted via ANYONE_CAN_PAY|NONE to some site?) which was created before some date (perhaps Aug 1st 2013) gets entered into a lottery, perhaps with some weight to inverse-btc days destroyed. Big BTC payouts in the lottery to encourage people to dig up old and inactive wallets with dust.