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

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


Former-commit-id: 3e9276f2a95d6fc7c10fbf91186d041dcba72611

core/router/route.go

@@ -40,6 +40,8 @@ type Route struct {
 	// route, manually or automatic by the framework,
 	// get the route by `Application#GetRouteByPath(staticSite.RequestPath)`.
 	StaticSites []context.StaticSite `json:"staticSites"`
+
+	topLink *Route
 }
 
 // NewRoute returns a new route based on its method,