Add Setuptools integration issue #261

These changes enable any user that installs `isort` to check his source
code from setup.py with the command `python setup.py isort`

I also checked isort package code with his command in tox and travis.

Acknowledgements: this is mostly inspired by flake8 setuptools integration,
see [flake8 doc](http://flake8.readthedocs.org/en/2.2.3/setuptools.html)

1 files changed, 10 insertions, 2 deletions

diff --git a/tox.ini b/tox.ini
index d8d7b905..94f069d7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,9 +4,17 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = py26, py27, py32, py33, py34, pypy
+envlist =
+    isort-check,
+    py26, py27, py32, py33, py34, pypy
 
 [testenv]
-commands = py.test {posargs}
+commands = 
+    py.test {posargs}
 deps =
     pytest
+
+[testenv:isort-check]
+commands = 
+    python setup.py isort
+deps =