Add echo.Binder() method

echo.go

@@ -293,6 +293,11 @@ func (e *Echo) SetBinder(b Binder) {
 	e.binder = b
 }
 
+// Binder returns the binder instance.
+func (e *Echo) Binder() Binder {
+	return e.binder
+}
+
 // SetRenderer registers an HTML template renderer. It's invoked by `Context#Render()`.
 func (e *Echo) SetRenderer(r Renderer) {
 	e.renderer = r

echo_test.go

@@ -333,3 +333,10 @@ func request(method, path string, e *Echo) (int, string) {
 	e.ServeHTTP(req, rec)
 	return rec.Status(), rec.Body.String()
 }
+
+func TestEchoBinder(t *testing.T) {
+	e := New()
+	b := &binder{}
+	e.SetBinder(b)
+	assert.Equal(t, b, e.Binder())
+}