Support for Expand

We should add support for Expand, which allows you to expanding the response data.
This will help api's create less latency when making requests.

e.g Say you want to obtain all the Accounts with the addresses.

Currently the only way to do so would be to make Several requests
First obtain the Accounts. => 10 Accounts.
Then obtain the Addresses which would require 10 additional requests.

But Ideally we should support expand to for all entities.
I have a suspicion that this will aid in obtaining user notification from the api, but I haven't tested yet.

This should go into consideration for v6.

-Grant