asynchronous replies
don't generate derived parameters in virtual driver
Merge pull request #2 from oceanobservatories/async

Async
Rough work to get platform driver functioning inside ZMQ wrapper
Rough work to get platform driver functioning inside ZMQ wrapper
Merge branch 'platform' of https://github.com/oceanobservatories/mi-instrument into platform
Merge pull request #3 from oceanobservatories/platform

Rough work to get platform driver functioning inside ZMQ wrapper
Merge changes from marine-integrations, remove ion dependencies
Merge pull request #4 from oceanobservatories/richard

Merge changes from marine-integrations, remove ion dependencies
fixing instrument driver unit tests for ION cleanup