Gradle script update.

ksdtoolkit-core/build.gradle.kts

@@ -2,12 +2,17 @@
  * Subproject: "ksdtoolkit-core".
  *
  * @author [Siniša Sovilj](mailto:sinisa.sovilj@unipu.hr)
+ * @author [Krešimir Pripužić](mailto:kresimir.pripuzic@fer.hr)
  */
 
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
     id("org.jetbrains.kotlin.jvm")
+
+    if (JavaVersion.current().isJava11Compatible) {
+        id("org.openjfx.javafxplugin") version "0.0.9"
+    }
 }
 
 tasks.withType<Jar> {
@@ -20,9 +25,7 @@ dependencies {
     implementation("org.jetbrains.kotlin:kotlin-reflect")
 
     testImplementation("org.jetbrains.kotlin:kotlin-test")
-
     testImplementation("org.jetbrains.kotlin:kotlin-test-junit")
-
     implementation("org.hamcrest:hamcrest-all:1.3")
 
     implementation("ch.qos.logback:logback-classic:1.2.3")
@@ -41,6 +44,10 @@ compileTestKotlin.kotlinOptions {
     jvmTarget = "1.8"
 }
 
+javafx {
+    modules("javafx.controls", "javafx.fxml", "javafx.graphics", "javafx.swing")
+}
+
 repositories {
     mavenCentral()
 }