Removing python 3 from Travis build and tox.

.travis.yml

 language: python
 python:
   - "2.7"
-  - "3.2"
-  - "3.3"
 
 install:
   - "pip install -r requirements.txt"

tox.ini

 [tox]
 skipsdist = True
-envlist = py27,py31,py32,py33
+envlist = py27
 
 [testenv]
 deps =
-    py27,py31: mock
+    mock
     pexpect
     -r{toxinidir}/requirements.txt