Make trinity conform to standard genesis.json standard from EIP-1085

[pipermerriam]

What is wrong?

ethereum/EIPs#1085

How can it be fixed

Implement the spec

[pipermerriam]

Things that need to be done for this:

New CLI option

First, new CLI option --genesis which expects to be passed the filesystem path to a valid genesis JSON file. When --genesis has been provided we will require that --data-dir is also specified to avoid accidental collision with the mainnet and ropsten directories until we sort this API out a bit.

Validation of genesis data

Next we need validation for the genesis JSON. A simple function which takes the parsed JSON and raises an eth_utils.ValidationError if it is not valid.

Update the ChainConfig class

Next the trinity.config.ChainConfig class needs to be updated to include this genesis data. This includes:

• New attribute chain_id that needs to be set on the ChainConfig class and probably stored on whatever Node class is used.

Setting genesis header

Next, in trinity.chains.get_chaindb_manager and trinity.chains.initialize_database we need to setup the database. We'll need the chain_class to do this. When --genesis has been specified, we need to use chain_class.from_genesis(...) to initialize the data dir. Ideally, we should be able to convert how the mainnet and ropsten chains are initialized to use the same mechanism, maintaining a local copy of the mainnet and ropsten genesis JSON (and probably validating them against the genesis header values from the py-evm package).

Part of this is going to be dynamically configuring the vm_configuration for the chain class from the provided genesis data.