Falling back to use pytest on travis

Unfortunately we can't use tox to test the package on travis
because when we start tracking coverage from the tox run, we
can't obtain the coverage exactly because tox runs the tests
in another process :(

Author: nicoddemus

.travis.yml

@@ -1,17 +1,18 @@
 language: python
-python: 2.7
-env:
-  - TOX_ENV=py26
-  - TOX_ENV=py27
-  - TOX_ENV=py32
-  - TOX_ENV=py33
-  - TOX_ENV=pypy
+python:
+  - 2.6
+  - 2.7
+  - 3.2
+  - 3.3
+  - 3.4
+  - pypy
 
 install:
-  - pip install tox coveralls --use-wheel
+  - pip install coveralls --use-wheel
 
 script:
-  - coverage run --source=pytest_mock.py runtox.py -e $TOX_ENV
+  - python setup.py develop
+  - coverage run --source=pytest_mock.py runtests.py
 
 after_success:
   - coveralls

runtox.py renamed to runtests.py

@@ -1,3 +1,3 @@
 # simple pytest wrapper so we can execute it using "coverage run"
-import tox, sys
-sys.exit(tox.cmdline())
+import pytest, sys
+sys.exit(pytest.main())