Corrected typo in GenericDomainClassJSONMarshallerUnitSpec.groovy. Added example of virtual and serializer usage to readme. Description of serializer and virtual seemed to be confused (reveresed), so I fixed that too.
Added .DS_Store to gitignore file. Removed .DS_Store files accidentally added to repo
Merge pull request #18 from quad64bit/master

Added example of virtual and serializer usage to readme, corrected errors