Use one window for all specs in the suite on more integration tests

I just integrated the specs on the following tests into a single window:

* CSSUtils-test
* ExtensionUtils-test
* Menu-test
* ProjectManager-test
* WorkingSetView-test

@jasonsanjose Want to review these too? Most were pretty simple to join and all tests are passing fast!!

Is so much nicer to run all integration tests now :)