[STF] added test class to test transport modes

As it is uncommon to force a specific transport mode and testing local
will almost ever result in Socks5 direct connections this test class
ensures that the other transport will also work as expected.

Change-Id: I617522369f687aa5e0603e443f22fdf2629397a0
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1048
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>