Resolve holders by allowing the issuer to invoke forced settlement if the asset has a settlement_price.

The Gridcoin MPA does not have the permission "override_authority: Issuer may transfer asset back to himself" as it was surrendered in the pursuit of decentralization. https://steemit.com/bitshares/@cm-steem/should-the-bitshares-committee-surrender-overreaching-mpa-permissions

There are currently only 4 holders of the GRIDCOIN MPA, I attempted to 'settle' my balance but without a price feed it doesn't work - we could potentially approach the 3 other users with the correct instructions to resolve the current black swan state, but if in the future we had 100+ holders this would be far more difficult.