Added .podspec to project

I didn't find this listed in available pods so I created the .podspec. I tested locally and it works fine, however using pod spec lint throws a warning about having to specify a tag to use. I didn't specify one since there are currently none. For this to be listed in the cocoapods repo, the project may have to be tagged and have that added to the s.source info for it to pass the tests and be accepted.