Separate Account initialization from Account deployment.

[ericnordelo]

Currently, we are deploying the Account if some conditions are met directly from initialization. This has some problems like nile automatically trying to deploy an Account in the send command if the account doesn't exist (not sure if this was the expected behavior), and also, deployment attempts when Account is used in NRE. I think it would be helpful for clarity and development to decouple these processes.

[andrew-fleming]

Also, tackling this issue should include adding deploy_account to Nile's documentation of the Account API (following the merge of #334)