The current code would match floater transactions even if they're years apart. Let's set a max date skew of say 7 calendar days, and not match if the difference is bigger than that.

Also, the floater-matching code should move from run.js to a newly created class MultiChunkAccountHistory.

• check if a mutationToSelf is in-chunk for both the sender and the receiver account. So maybe the sender composes chunks of implied bank-to-bank transactions, and sends those to the receiver, who then tries to match them up with AccountHistoryChunk#mixIn or something close to that.