fix for mavericks
work with more than one version of osx
Updated gem source.
Renamed sync type to sync_ to avoid Ruby 2.1 item with same name.
Adds compatibility for Ruby 2.1.x

Changes KLASS_OF macro which wasn't compatible with the new Ruby
version.

Fixes #22
Merge pull request #21 from dragonfax/master

Support for Mavericks OSX 10.9
Merge pull request #25 from gilles-leblanc/ruby21compat

Ruby 2.1.x compatibility
pre version to test out released gem
update changelog