Add application gradle option to allow running custom Kt files

build.gradle.kts

@@ -139,6 +139,13 @@ tasks.withType<KotlinCompile> {
 // ------------------------------------------------------------------------------------------------------------------ //
 
 project.setProperty("mainClassName", applicationMainClass)
+
+application {
+    if (hasProperty("application")) {
+        mainClass.set("${property("application")}Kt")
+    }
+}
+
 tasks {
     named<ShadowJar>("shadowJar") {
         manifest {
@@ -297,4 +304,4 @@ if (properties["openrndr.tasks"] == "true") {
         group = " \uD83E\uDD8C OPENRNDR"
         dependsOn("jpackageZip")
     }
-}
+}