installing python

problem seems to be that _test.capture fails to import:

```
  File "runtests.py", line 12, in <module>
    import _pytest.capture
  File "/home/travis/virtualenv/python2.7.6/lib/python2.7/site-packages/_pytest/capture.py", line 9, in <module>
  File "/opt/python/2.7.6/lib/python2.7/tempfile.py", line 32, in <module>
    import io as _io
  File "/opt/python/2.7.6/lib/python2.7/io.py", line 51, in <module>
    import _io
ImportError: /home/travis/build/nicoddemus/cx_freeze_pytest_example/bin/_io.so: undefined symbol: _PyLong_AsInt
```