Added draft of modified travis-ci workflow to build pymbar-dev conda package.
Attempted workaround for version travis conda issue.
Updated setup.py with latest mdtraj version of writing of version.py
Restrict travis to just test python 2.7.
Merge pull request #80 from jchodera/conda-ci

pymbar-dev conda package creation via travis-ci
Updated README with conda installation info.
Updated encryption key in travis.yml
Merge pull request #79 from mrshirts/master

Accidentally sets the wrong uncertainties to zero
resolving issues between master and nk, all in pymbar/__init__.py