build: remove 2.6 testing on travis

Python 2.6 seems to be no longer supported on travis.ci so we're letting
it drop here. We're retaining testing on 2.6 in tox for now though.

Author: scanny

.travis.yml

@@ -3,7 +3,6 @@ python:
   - "3.6"
   - "3.5"
   - "2.7"
-  - "2.6"
 # command to install dependencies, e.g. pip install -r requirements.txt --use-mirrors
 install: pip install -r requirements.txt
 # command to run tests, e.g. python setup.py test

tox.ini

@@ -12,13 +12,12 @@ python_classes = Test Describe
 python_functions = it_ they_ and_it_ but_it_
 
 [tox]
-envlist = py26, py27, py33, py34, py35
+envlist = py26, py27, py34, py35, py36
 
 [testenv]
 deps =
     behave
     lxml
-    mock
     pyparsing
     pytest
 
@@ -35,16 +34,10 @@ deps =
     pyparsing
     pytest
 
-[testenv:py33]
-deps =
-    behave
-    lxml
-    pyparsing
-    pytest
-
-[testenv:py34]
+[testenv:py27]
 deps =
     behave
     lxml
+    mock
     pyparsing
     pytest