Added new() to IResourceClass

Added `new(dataOrParams? : any) : T;` to `IResourceClass<T>` to allow creation of a new instance of the resource using the `new` keyword, which is required to create a new resource object of type `T`. 

In the [AngularJS documentation example](http://docs.angularjs.org/api/ngResource/service/$resource) this change would allow for line 27 `new CreditCard({number:'0123'});` where `CreditCard` is `IResourceClass<CreditCard>`. Without this change we get `error TS2083: Invalid 'new' expression.` when new-ing the resource.