Start test runner directlt from JUnit runner

In the JUnit runner, tests were executed by registering runs in a static map (singleton).

This patch changes the FitNesseSuite runner to run a test suite directly. It builds a context, starts the executer and collects the results in a simple and transparent way.

Note that no FitNesse server is started anymore. This means that the @Port annotation is no longer needed.

This patch is related to #383.