* Drop support for EOL Python 2.6
* Use more helpful assertIn/NotIn instead of assertTrue/False
* Drop support for EOL Python 3.3
* Remove redundant Python 3.3 code
* Restore code for RHEL 6 and virtualenv for Py2.7
* Revert pipstrap.py to upstream
* Merge py26_packages and non_py26_packages into all_packages
* Revert changes to *-auto in root
* Update by calling letsencrypt-auto-source/build.py
* Revert permissions for pipstrap.py
Remove the old bootstrap scripts, which have been subsumed into letsencrypt-auto-source/pieces/bootstrappers. They no longer need to be dispatched among manually: everyone can just run letsencrypt-auto --os-packages-only, regardless of OS.
Make the root-level le-auto a symlink to the canonical version. It should thus still work for people running le-auto from a git checkout.
