1.8.0 - Better ids for fixture unions

New:

• fixture_union now accept a non-None value for ids. It also has a new idstyle argument allowing users to change the style of ids used. Finally pytest_parametrize_plus relies on this ids argument to set a more readable list of ids for the created union. Fixes #41.

Misc:

• Added non-regression test for fixture order. It passes already for all recent pytest versions (after 3.3). Fixes #42

See documentation page for details.