Project direction: Use of in-process, in-memory Blockchain

[ulope]

We intend to use an in-memory, in-process Ethereum Blockchain implementation (pyethereum's tester module to be specific) to implement the Blockchain parts of the PoC.

The reason for this is that it will make certain parts of the implementation much easier since we won't have to expect and deal with many of the complexities (e.g. chain reorgs, network communication, requirement for internet access etc.) of the "real" BC.

The drawback is that the transactions etc. that happen during the operation of the PoC will not be visible on any public BC.

The goal of this issue is to reach agreement on this so we can proceed with the implementation.

[ewaldhesse]

agreed