Fixes JIRA issue SGF-231 - user is unable to specify Order Policy with Serial Gateway Senders.
Fixes JIRA issue SGF-232 - user is unable to specify Order Policy with a Serial Async Event Queue.  Plus, made additional changes to the GatewaySenderFactoryBean class and associated tests/code for SGF-231.
Fixed failing test cases in the SubRegionSubElementTest class due changes that fixes SGF-231 and SGF-232.
Reverted the value of the parallel attribute in the Gateway Sender for the 'Orders' Replicate Region in the SubRegionSubElementTest class.