What does this implement/fix? Explain your changes.

Enables embedded tests on Travis

Does this close any currently open issues?

Closes #224

Any other comments?

Enabling the test exposed a few bugs in PY2/PY3 pythonnet on Linux. I've opened tickets for a couple of them.
I've added the error messages to the tests and a conditional ignore testing. As the issues get fixed, the conditional on the tests can be removed.