Create contentType dependent closures for type-specific parsing.

Its all about content negotiation - dealing with the Accept header properly.

Something like:

gserv.http{
    get("/"){
        contentType(["application/json", "text/json"]){
            ///parse JSON
        }
         contentType(["application/xml", "text/xml"]){
            ///parse XML
        }
    }
}
