TST: get travis working on Py26 and Py27

I had to rely on conda for Py26. Waiting for wheels for later

TST: try to get Py2.6 on travis

TST: use conda for python 2.6

Fix bug in .travis.yml

Fix .travis.yml

TST: Try to fix travis

TST: fix travis on 2.7
TST: Add Python 3.3 to travis
Merge pull request #2767 from GaelVaroquaux/my_master

TST: get travis working on Py26 and Py27