fixture is not extending template if range set as items

example:

    User:
        user (template):
            firstName: <firstName()>

        user_{first, second, third} (extends user):
            lastName: <lastName()>

in result ```user_first```, ```user_second```, ```user_third``` will not get first name set.
Add test for all types of template definitions and extensions and fix a few more cases, refs #143