Fixed test_alphabet to clear the numconv cache (and be more py.testy)
Fixed test_alphabet to clear the numconv cache (and be more py.testy)

skirsdeda/django-treebeard,tabo/django-treebeard,django-treebeard/django-treebeard,skirsdeda/django-treebeard,skirsdeda/django-treebeard,django-treebeard/django-treebeard,tabo/django-treebeard,skirsdeda/django-treebeard,tabo/django-treebeard,django-treebeard/django-treebeard,tabo/django-treebeard