posting new offers with Mangrove.js should NOT use market subscription

[jkrivine]

Buying and selling via market.ts no longer use subscription but fold directly through the log of the tx receipt. A similar scheme should be used in OfferLogic.ts for the newOffer/updateOffer functions.

It is faster for the maker and more robust. Synchrony with the cache of the OB is irrelevant as the maker knows it is up to date with the state of Mangrove.