To do this before we have any real TransportLayer implementations, we will need to write a mock TransportLayer for the sake of getting the tests hooked up.

1. Implement a TransportLayerTestSuite class
add a new scons library for this
add methods for each test from the test plan
2. Implement a mock TransportLayer
should implement all TL methods as basically as possible to pass tests
3. Run the mock TL through the TransportLayerTestSuite
add a new scons cpptest target that uses the above library