Adding include paths to CLI testrunner

I think it would be useful to have something like --include=PATH for the CLI testrunner. That way you can setup your testsuite without having to know about the actual location of the test suite in the directory structure. The call to the CLI testrunner then can take care of setting up the enviroment using --include. No need to repeat

```
require =("../lib/LibrarySubjectToBeTested");
```

but do

```
require('LibrarySubjectToBeTested");
```

and simply call

```
nodeunit --include=../lib/
```

I implemented a patch that would add this functionality to the testrunner. Have a look at it: 1db0b284d70829d4fe5f8a1fe20274562cdc5bd8
Please let me know what you think and if there's anything I missed. If you like it, feel free to pull it in.

Commencez par examiner le commit 1db0b284d70829d4fe5f8a1fe20274562cdc5bd8 et le point d’entrée du CLI testrunner. Vérifiez comment l’option proposée --include=PATH configure l’environnement de recherche des modules, puis exécutez la suite de tests existante ; le travail est terminé lorsque nodeunit --include=../lib/ permet de require LibrarySubjectToBeTested sans chemin relatif.

Rédigé par le modèle d'indexation à partir du texte de l'issue.