Sync requirements and add license info

Follow guidelines in:
https://packaging.python.org/requirements/

* Make sure the same list of packages are in setup.cfg and
  requirements.txt
* install_requires reqs in setup.cfg should be "Abstract" with
  no version information
* Add License information for each package

Fixes kubernetes-client#131

requirements.txt

@@ -1,9 +1,9 @@
-certifi >= 14.05.14
-six>=1.9.0
-python_dateutil >= 2.5.3
-setuptools >= 21.0.0
-urllib3 >= 1.19.1
-pyyaml >= 3.12
-oauth2client >= 4.0.0
-ipaddress >= 1.0.17
-websocket-client>=0.32.0
+certifi>=14.05.14 # MPL
+six>=1.9.0  # MIT
+python-dateutil>=2.5.3  # BSD
+setuptools>=21.0.0  # PSF/ZPL
+urllib3>=1.19.1  # MIT
+pyyaml>=3.12  # MIT
+oauth2client>=4.0.0  # Apache-2.0
+ipaddress>=1.0.17  # PSF
+websocket-client>=0.32.0 # LGPLv2+

setup.py

@@ -28,13 +28,16 @@
 # http://pypi.python.org/pypi/setuptools
 
 REQUIRES = [
-    "urllib3 >= 1.19",
-    "six >= 1.10",
     "certifi",
+    "ipaddress",
+    "oauth2client",
+    "setuptools",
+    "six",
+    "urllib3",
     "python-dateutil",
     "pyyaml",
-    "oauth2client",
-    "ipaddress"]
+    "websocket-client",
+]
 
 setup(
     name=PACKAGE_NAME,