Add a bug in the todo list (commits with only deleted files)
Fix unit tests: the koha-qa dir name should not be hardcoded
Fix: the perlcriticrc path should be build from the package path.

On this way, the perlcriticrc file is used on launching tests and using
the koha-qa.pl script.
Update README: PERL5LIB has to contain the qa-tools directory