Set known_third_party for isort

When run as a git-hook, isort has a lot of trouble identifying
third-party libraries. This adds the currently used third-party
libraries explicitly in the configuration.

The list was obtained by temporarily adding the seed-isort-config hook
(https://github.com/asottile/seed-isort-config#seed-isort-config)

Closes #13

Author: goerz

setup.cfg

@@ -20,7 +20,7 @@ ignore_directives=doctest
 ignore_messages=(Hyperlink target "[^"]+" is not referenced\.$)
 ignore_roles=cite
 
-[isort]
+[tool:isort]
 known_first_party = qdyn
 force_single_line = False
 lines_after_imports = 2
@@ -29,3 +29,4 @@ use_parentheses = True
 multi_line_output = 3
 include_trailing_comma = True
 skip = src/qdyn/__init__.py
+known_third_party = click,git,matplotlib,numpy,pkg_resources,pytest,qdyn,qutip,scipy,setuptools,six,sphinx