check doesnt seem to work correctly for 'Module's and 'EGraph's

[KristopherBorn]

The check doesnt seem to work correctly for wrong and not existing file names respectively.

In die example below the HenshinResourceSet seems to be evaluted to be correct. (line 48)

The afterwards usage to load a Module and EGraph involve wrong file names. Files with the names are not existing. Related error markers are expected but not present.

Related to performance it semes to be suitable to make use of the exists() method of org.eclipse.core.resources.IResource.
see.: http://help.eclipse.org/neon/topic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/core/resources/IResource.html#exists--