Add a transaction status interface for the connection manager and implement it in TxConnectionManager

The ConnectionManager needs a transaction status interface
such that resource adapters can check the active status of the transaction assoication.

This should be similar to the TransactionTimeoutConfiguration
where only the TxConnectionManager implements it.

If the transaction is not active then an exception should be thrown.

The resource adapters (jdbc and jms) need to add a check for transation active to their checkState methods).