Critical protocol changes
-------------------------

* date
* The JSON field "metaData" changing to "meta".
* RPC ledger will no longer take "ledger", use "ledger_hash" or "ledger_index".
* "closedLedger" events:
** "hash" DEPRECATED: use "ledger_hash"
** "seqNum" DEPRECATED: use "ledger_index"
** "closeTime" DEPRECATED: use "close" or "close_human"
* stream "rt_accounts" --> "accounts_proposed"
* stream "rt_transactions" --> "transactions_proposed"