linking and running agent tests

this PR follows the advice (albeit not incredibly helpful advice) [here](https://code.google.com/p/googletest/wiki/Primer#Important_note_for_Visual_C++_users) in order to actually run tests living in the basic agent unit test library. The associated targets are minimally linked (i.e., agent modules don't link directly against `gtest`, only `baseagentunittests`)