Add new module icon
Add new capability to add instance of the module
Merge exceptions.php into lib.php
Fix standard file headers and clean up
Fix module description
Do not try to attempt to automatically create meta course link

This basically reverts the feature implemented by Matt Gibson in the pull
request #5. I found it a bit buggy but more importantly, conceptually wrong.
This module should do one thing and do it well. Any attempt to do something on
behalf of the course teacher may lead to unpredictable results (e.g. the fact
that the module deleted the meta course link on its removal).
Fix strict standard warning in the cron log
Fix invalid link URLs
Remove non-English strings

These will be re-imported into AMOS once this module is published.
Overall code cleanup

Among other things, this removes the recently added feature that already
referenced courses are not offered in the settings form. This did not work well
when editing existing instances.