- update to play 2.3

I have a play 2.3 application and wanted to use your great iron cache plugin. So i updated it to the play 2.3 version. Some code adaption was needed because the WS 2.3 api needs a implicit Application instance. That cause a infinite loop in the enabled method to get a rid of this is use URLConnection instead WS in the enabled method. That is not ellegant but works, added a TODO comment. 

Also setup the Multi Project to perform tests on the sample from the root project.