Apply isort to tests.d3viz sub-package modules

tests/d3viz/models.py

 import numpy as np
+from six import integer_types
 
 import theano
 import theano.tensor as tt
 
-from six import integer_types
-
 
 class Mlp(object):
     def __init__(self, nfeatures=100, noutputs=10, nhiddens=50, rng=None):

tests/d3viz/test_d3viz.py

+import filecmp
 import os.path as pt
 import tempfile
-import filecmp
-
-import pytest
 
 import numpy as np
+import pytest
 
 import theano as th
 import theano.d3viz as d3v
-
+from tests.d3viz import models
 from theano.d3viz.formatting import pydot_imported, pydot_imported_msg
 
-from tests.d3viz import models
 
 if not pydot_imported:
     pytest.skip("pydot not available: " + pydot_imported_msg, allow_module_level=True)

tests/d3viz/test_formatting.py

 import numpy as np
-
 import pytest
 
 import theano as th
-
 from theano.d3viz.formatting import PyDotFormatter, pydot_imported, pydot_imported_msg
 
+
 if not pydot_imported:
     pytest.skip("pydot not available: " + pydot_imported_msg, allow_module_level=True)