* New UnknownTransaction exception that is raised when using get_transaction with an unkown trx_id
* New function is_transaction_existing which returns false, when a trx_id does not exists
* beempy info does not show information for a trx_id
* broadcast from TransactionBuilder can now return a trx_id, when set trx_id to True (default)
* sign and finalizeOp from Hive and Steem return now the trx_id in a field
* add export parameter to all broadcast commands in beempy
* When setting unsigned in beempy, the default value of expires is changed to 3600