Add testing for the ExecutionThread and check it keeps in good state according to the server state.
Remove the manual runners. Using the IDE launches test twice due to the AllTests running all tests again.
Better naming of things. Remove redundant/useless getters.
Bugfix, we were not calling the onStop() methods of the executables.

This was identified because the workerPool was not being stopped nicely even after the server was.
No wonder, the workerPool is an executable and we were not stopping it properly.