- Temporary work directories created for modules whose compilation process does not work properly (e.g. because there is no associated C code) are now deleted immediately instead of waiting until the process ends. Note that we could probably make it so that we do not create then delete too many directories by checking if the C implementation works before creating the directory. - KeyData objects associated to unversioned modules are now created, so that the module can be re-used by another unversioned key in the same process. They are not saved though. - Versioned but broken keys can now also re-use modules. - The version part of unversioned keys is now ignored in the module hash, just in case there would be multiple unversioned keys whose string representation of the version would be different. - Added a 'debug_counter' utility function that can be used for debugging (may be moved later to a more generic place if someone wants to re-use it in another module)