Gamry Potentiostat trigger control Testing & OPI

The Gamry was created fairly quickly for IMAT in #2642 but it does not have a working emulator and IOC test framework test. The emmulator exists but Lewis needs to be modified to make it run; the message handle needs to be exposed from inside lewis so we can post unsolicited messages.
Tasks:

1. Fix Lewis by with talking with Lewis or monkey patching it
1. Write tests
1. Create OPI