Add tox file and clean up a lint error

.travis.yml

@@ -8,4 +8,4 @@ install:
   - pip install -e .
 
 script:
-  - flake8 --max-line-length=100 --max-complexity=24 --statistics --benchmark symposion
+  - flake8 symposion

symposion/boxes/utils.py

@@ -7,7 +7,7 @@ except ImportError:
 
 def load_path_attr(path):
     i = path.rfind(".")
-    module, attr = path[:i], path[i+1:]
+    module, attr = path[:i], path[i + 1:]
     try:
         mod = import_module(module)
     except ImportError, e:

tox.ini

@@ -0,0 +1,3 @@
+[flake8]
+ignore = E501,E265
+exclude = migrations