Consider maintaining consistent language in readme

[iamgollum]

Consider the following example:

curl -u <agent_name>:<agent_password> <account_url>/api/v1/info

curl -u <account_admin_agent_name>:<account_admin_agent_password> -X PATCH \
    <account_url>/api/v1/identities/<agent_name> \
    -H 'Content-Type: application/json' \
    -d '{ "role": "TRUST_ANCHOR" }'

<account_admin_agent_password> is really the same thing as <agent_name>

I would be happy to submit a PR for this and start OS contributing if we can get a 'consensys' on the language that should be used here.