Python 2 is a bit more picky with respect to
the correct name of the module. If passing "db"
to a module called dbcore, it will exit with
a SystemError.
* Added unit test for this
* Provided an option for easier debugging such issues:
Setting env var KLAYOUT_VERBOSITY will enable debug levels on Python
modules (and all other binaries). Plugin loading issues can
be debugged by setting KLAYOUT_VERBOSITY=21.