Lotus msgs

[dholms]

Lots of the ground work for our server!

This includes routes for:

• registering a key pair wtih the server
• getting the balance of an account
• getting the provider's address
• formatting a message with nonce & gas estimates
• signing a message

Some of this is done with mock data. For instance, the server only has one private key right now (as opposed to one per user), and the signing route does not yet sign arbitrary messages.