Custom JSON-RPC for Consortium Chains

[ricmoo]

By enabling a given account to have a specific Chain ID and JSON-RPC node it will make it much simpler to maintain testnet and mainnet accounts, and more importantly maintain private/consortium accounts along side regular ether.

There will need to be some mechanism to notify the user of which chain they are using and to make sure there is some way for apps to understand the scope of the account.

[ricmoo]

Per-account chain ID has been added. The ethers.objc library has also had Rinkeby and Kovan added to it, so those networks will also be available in the next version of Ethers Wallet.

Custom nodes needs to be added, and requires some thought for how to (if to?) store in the keychain data.

[ricmoo]

Re-opening to track custom node.