Includes the fixes from tbtc.js 0.18.1, around retries and redemption fees.
Makes the Discord link in the dApp open in a new tab, as folks were getting
worried when they ran into trouble and the link navigated them away from the
dApp (even though the dApp responds well to back buttons).
Clarifies errors when a deposit is in a liquidation or failed setup state.
This PR does a few small things: