Update example Podfile.
Use single quotes for consistency.
Merge pull request #204 from Quick/fix-cocoapods-instructions

Update example Podfile.
Update contributing guidelines.

* Add advice for core members on creating pull requests.
Merge pull request #205 from paulyoung/update-contributing-guidelines

Update contributing guidelines.
Update README.md
Merge pull request #207 from palewar/patch-1

Update README.md for correct CocoaPods gem
Merge remote-tracking branch 'upstream/master'