Add test_runner option with two possible values: pytest and nosetests.

[svetlyak40wt]

No description provided.

[ionelmc]

You need to add nose to the dependencies (and the coverage plugin maybe?).

[svetlyak40wt]

Good catch! Forgot them.

[ionelmc]

I think I forgot to mention the help section in the readme: https://github.com/ionelmc/cookiecutter-pylibrary/blob/master/README.rst#usage - there should be row about the test_runner variable.

One more thing: I wonder if the option name for nosetests shouldn't be just nose. What do you think?

[ionelmc]

Look good. I've pushed it to the develop branch. Gonna push it to master after some testing, seems appveyor is useless.

[svetlyak40wt]

Ok, thank you!