Merge pull request #36 from ryanvarley/master

Kepler-31
Merge pull request #37 from ryanvarley/master

Typo corrected in Kepler 68c.
Merge branch 'master' of https://github.com/hannorein/open_exoplanet_catalogue
Typo.
NN Ser update. http://arxiv.org/abs/1305.6494
Cleanup and description added for NN Ser.
Merge branch 'master' of https://github.com/hannorein/open_exoplanet_catalogue