Added getModule method to ModuleInstaller.

The getName method in ModuleInstaller becomes available after calling addModule.

This particularly heplful for setting up the module. As an example instead of using :

$this->setActionRights(1, 'Providers', 'Index');

we would use

$this->setActionRights(1, $this->getModule(), 'Index');

and have less chance to have typo errors
@ghazispeakserve What I think is a bit odd, is that the getter 'getModule' returns $this->name. It would be more logical if the property is called 'module', so you can return $this->module.