Update to osx 10.9

- Update to osx 10.9
- Install osx software with brew cask
- Update Ruby to 2.0-p247
Fix typos in README
Install Ruby 1.9.3-p353
Replace ruby 2.0 with 2.1
Merge pull request #3 from fs/update-to-osx-10-9

Update to osx 10.9