Use `add` instead of `set` in x2m fields

set was removed from the tryton API
See: tryton/trytond@16b6be11a7211d9dfdd22b0e068a5e741114904e
No default address is created with party
Remove local eggs from flake8 check
Add test command and fix depends

The tryton test API has changed and now expects the
configuration to be preset and DB_NAME to be there in
the environment variables.

The suite makes it convenient to run tests using
`python setup.py test` and `python setup.py test_on_postgres`

See tryton/trytond@95b51d3893253414e4e318ed49f056cbefbcd7da

Also install nereid-test from repo
Merge pull request #199 from sharoonthomas/develop

Make the module work on 3.2