Fix mass of KOI-55 b

Fix mass of KOI-55 b to match discovery reference: http://www.nature.com/nature/journal/v480/n7378/pdf/nature10631.pdf (Table 1).
Merge pull request #80 from orome/patch-1

Fix mass of KOI-55 b
Merge branch 'hat' of https://github.com/migueldvb/open_exoplanet_catalogue into newhat
Running cleanup script.
Fixed minor typos in README file