Smart contract update

[tjayrush]

The smart contract should take an additional parameter: reason. Right now, it only takes chain and hash.

In this way, we can publish different records -- in fact, anyone can publish any record for any reason.

In our case, we want to publish three data sets:

publish(chain, "unchained-index", hash)
publish(chain, "timestamps", hash)
publish(chain, "abis", hash)
publish(chain, "names", hash)

Note that the client software (i.e. the software reading the data) can decide what to do with it. If they only want to read the names database from the mainnet, they can.

Note: The first three databases above are 'reproducible' and 'immutable'. The names database is not. (It matters because end users don't have to trust the first three -- if they don't they can reproduce it themselves, while the last one (names) is not reproducible -- no less useful, but not reproducible.)