Install docker-py from GitHub

Just use requirements.txt for now, as doing it in setup.py is a pain.

requirements.txt

@@ -0,0 +1 @@
+git+git://github.com/dotcloud/docker-py.git@4fde1a242e1853cbf83e5a36371d8b4a49501c52

setup.py

@@ -32,12 +32,7 @@ setup(
     packages=['plum'],
     package_data={},
     include_package_data=True,
-    install_requires=[
-        'docopt==0.6.1',
-        'docker-py==0.2.2',
-        'requests==2.0.1',
-        'texttable==0.8.1',
-    ],
+    install_requires=[],
     dependency_links=[],
     entry_points="""
     [console_scripts]