Add support for HTTP 405

router.go

diff --git a/router.go b/router.go
index 7716dc7..1028c03 100644
--- a/router.go
+++ b/router.go
@@ -313,6 +313,18 @@
 		}
 	}
 
+	// Handle 405
+	for method, _ := range r.trees {
+		if method == req.Method {
+			continue
+		}
+
+		if handle, _, _ := r.trees[method].getValue(req.URL.Path); handle != nil {
+			http.Error(w, "405 method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+	}
+
 	// Handle 404
 	if r.NotFound != nil {
 		r.NotFound(w, req)