* Remove xunit dependency from testdriver
* swap expected/actual as needed
* Convert Test.Common to nunit
* port hosting unit tests to nunit
* port batchparser integration tests to nunit
* port testdriver.tests to nunit
* fix target to copy dependency
* port servicelayer unittests to nunit
* more unit test fixes
* port integration tests to nunit
* fix test method type
* try using latest windows build for PRs
* reduce test memory use
* Fix serialization tests & don't block thread
- Fixed potential null ref when closing streams
- Always clean up serialization queue if an error occurs
- Stop blocking dispatcher thread by not awaiting task that processes the message
- Improved error logging in EventFlowValidator to help debug issues
- Close stream on exception
Added a method that handles serialization requests
Support splitting save over multiple requests to reduce overall message size
Added unit tests
String changes used a new version of the string tool for generation.
Will publish PR separately for the changes to build & localization
so this can run on Mac without .Net Core 1.0
