Removing travis python 2.7 testing, greenmine only works with python 3

.travis.yml

@@ -1,6 +1,5 @@
 language: python
 python:
-  - "2.7"
   - "3.3"
 services:
   - rabbitmq # will start rabbitmq-server

greenmine/projects/documents/api.py

@@ -3,7 +3,7 @@
 from rest_framework.permissions import IsAuthenticated
 
 from greenmine.base import filters
-from greenmine.base.api import ModelCrudViewSet,
+from greenmine.base.api import ModelCrudViewSet
 
 from . import serializers
 from . import models