Updates Grails sample project to Grails 2.2.1 and added grails wrapper so you don't need to install grails framework to run the project

1.  I was having trouble getting the sample running in Grails 2.2.1 (latest), so I moved the swagger files to /src directory from grails-app/resources. 

2. To make running of the app easier, I added the grails wrapper, so that you can just run grailsw run-app and it will automagically download correct grails framework version, all the dependencies, and startup the server.