Fix inability to pull multiple accounts in one user domain

[at4260]

Continuation of issue #13, but not urgent because there are no other test accounts to use.

When there is only one account per user domain, then the Intuit API and Python library aggcat returns:
<AggCatResponse 201>
<Investmentaccount object @ ----->
This is one object and allows attributes to be called on it.

However, when the user domain has multiple accounts (ex: Chase login/pw with a checking account, credit card, mortgage, etc), then aggcat returns:
<AggCatResponse 201>
<Accountlist object @ ----->

The aggcat documentation states that it is supposed to return this:
<Accountlist object [<Investmentaccount object @ 0x1090c9bd0>,<Loanaccount object @ 0x1090c9890> ...] @ 0x1090c9b10>
This allows the user to itierate through the list of accounts and then call attributes on it.

Currently, <Accountlist object @ -----> does not allow me to itierate through the list or call attributes, so I am not able to pull the account information from each account.

The authentication process (challenge response) will have a similar issue. Without being able to see the list of challenge questions, I won't be able to respond and authenticate the account.

Aggcat documentation:
https://aggcat.readthedocs.org/en/latest/api.html

Aggcat github:
https://github.com/glenbot/python-aggcat

[at4260]

Contacted owner of aggcat (glenbot). He is in the process of moving the API to use JSON instead of XML. After that is complete, my plan is to install the new library and refactor my code in order to fix this issue.