Institutions in config file short names and instances

[Kmccabe]

Would be nice to have the ability to specify more than one instance of an institution as we do with agents, i.e.,
{"institution": "amm.AMM", "number": 2}
would create two instances of the AMM institution.

Also, short names of institutions should not end with sequential numbers, but instead, start renumbering for each institution type. For example,
[
{"institution": "amm.AMM", "number": 2},
{"institution": "proposer.Proposer", "number": 1},
{"institution": "account.Account", "number": 2}
]
should result in short names: amm.AMM 1, amm.AMM 2, proposer.Proposer 1, account.Account 1, account.Account 2. If a naming conflict occurs it suggests a serious problem with naming unique institutions and throw an exception.