Added debug env to tox

A test can be run now in debug mode by running:
    tox -edebug <test_name>
e.g.
    tox -edebug test_create_table_duplicate

It is also possible to pass a regex so that you
don't run tests whose name contains the test_name
parameter. If you want just test_create_table to
run you can run just that test with:
    tox -edebug test_create_table$

Change-Id: If02cf5d9f5c44c67ac57689b83e3a2d6c42988fb
Merge "Added debug env to tox"