new feature: handle different param types in the exact same path pattern

implements https://github.com/kataras/iris/issues/1315


Former-commit-id: 3e9276f2a95d6fc7c10fbf91186d041dcba72611

_examples/miscellaneous/pprof/main.go

@@ -13,7 +13,9 @@ func main() {
 		ctx.HTML("<h1> Please click <a href='/debug/pprof'>here</a>")
 	})
 
-	app.Any("/debug/pprof/{action:path}", pprof.New())
+	p := pprof.New()
+	app.Any("/debug/pprof", p)
+	app.Any("/debug/pprof/{action:path}", p)
 	//                              ___________
 	app.Run(iris.Addr(":8080"))
 }