[Path] Integration Testing for Path

[buckbaskin]

see http://wiki.ros.org/unittest#ROS-Node-Level_Integration_Tests

not sure where the boundary between this and unittesting is, but I should have both. Path is the guinea pig for all of this.

[buckbaskin]

This should just verify that when a Path-extending node is running, it provides the correct interface. It doesn't need to be super specific.