Support for Type Parameters

At the moment it is only possible to use Type classes with a wildcard, thus loosing all type information

@import TypedCaseClass
 @(typedCaseClass: TypedCaseClass[_])(implicit request: RequestHeader, 
  messages: Messages){
   //...
 }

It would be nice, if something like this would be possible:

@import TypedCaseClass
 @[T](typedCaseClass: TypedCaseClass[T])(implicit request: RequestHeader, 
  messages: Messages){
   //...
 }

No files, tests, or entry points are identified. Start by reproducing the two template snippets and determine how the requested generic parameter syntax should preserve type information while keeping wildcard usage valid; done means the second example is supported without regressing the first.