Makes Kooby Class open (#815)

* Made Kooby open

* Kooby example

Author: vjames19

modules/jooby-lang-kotlin/src/main/kotlin/org/jooby/Jooby.kt

@@ -164,7 +164,7 @@ class KRouteGroup(b: Route.Props<Route.Group>) : Route.Props<Route.Group> by b {
 /**
   * Collection of utility class and method to make Jooby more Kotlin.
   */
-class Kooby: Jooby() {
+open class Kooby: Jooby() {
   fun <T:Any> use(klass: KClass<T>): Route.Collection {
     return use(klass.java)
   }

modules/jooby-lang-kotlin/src/test/kotlin/examples/kotlin/App.kt

@@ -1,14 +1,17 @@
 package examples.kotlin
 
 import org.jooby.Jooby
+import org.jooby.Kooby
 
-class App: Jooby() {
+/**
+ * Use Kooby to make Jooby more Kotlin.
+ */
+class App: Kooby() {
   /**
    * Configure your application
    */
   init {
-
-    get ("/") { ->
+    get ("/") {
       "Hi Kotlin"
     }
   }