Merge: MModule has a c_name

In compiler/, all entities have a `c_name` method to get a fully qualified mangled C identifier also usable to name files. All, except for one small class of indomitable entities that still holds out against the namespaces.

`c_name` where developed before the proposition of projects. This PR add a `c_name` for mmodules and update the places where its simple name was used.

Pull-Request: #898
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>