build.gradle: add javafx runtime dependency for other platforms

We have added the platform specific javafx runtime dependency, so the
addressbook is able to run locally.

However, the jar file generated on one OS cannot run on other OS. The
reason is that, java SE cannot initialize the graph render correctly
without corresponding javafx dependency for that other OS.

Let's add the javafx runtime dependency for all platforms (MacOS,
Window, Linux) so the jar file generated on one OS is able to run in
other OS [1].

[1]https://stackoverflow.com/questions/52653836/maven-shade-javafx-runtime-components-are-missing/52654791#52654791

build.gradle

@@ -2,18 +2,8 @@
 // For more details take a look at the Java Quickstart chapter in the Gradle
 // user guide available at http://gradle.org/docs/5.2.1/userguide/tutorial_java_projects.html
 
-import org.apache.commons.lang3.SystemUtils
 import org.gradle.api.tasks.testing.logging.TestLogEvent
 
-buildscript {
-    repositories {
-        mavenCentral()
-    }
-    dependencies {
-        classpath group: 'org.apache.commons', name: 'commons-lang3', version: '3.8.1'
-    }
-}
-
 plugins {
     id 'java'
     id 'jacoco'
@@ -51,26 +41,29 @@ test {
     useJUnitPlatform()
 }
 
-String platform
-if (SystemUtils.IS_OS_WINDOWS) {
-    platform = 'win'
-} else if (SystemUtils.IS_OS_LINUX) {
-    platform = 'linux'
-} else if (SystemUtils.IS_OS_MAC) {
-    platform = 'mac'
-}
-
 dependencies {
     String testFxVersion = '4.0.15-alpha'
     String jUnitVersion = '5.1.0'
     String javafxVersion = '11'
 
-    implementation group: 'org.openjfx', name: 'javafx-base', version: javafxVersion, classifier: platform
-    implementation group: 'org.openjfx', name: 'javafx-controls', version: javafxVersion, classifier: platform
-    implementation group: 'org.openjfx', name: 'javafx-fxml', version: javafxVersion, classifier: platform
-    implementation group: 'org.openjfx', name: 'javafx-graphics', version: javafxVersion, classifier: platform
-    implementation group: 'org.openjfx', name: 'javafx-media', version: javafxVersion, classifier: platform
-    implementation group: 'org.openjfx', name: 'javafx-web', version: javafxVersion, classifier: platform
+    implementation group: 'org.openjfx', name: 'javafx-base', version: javafxVersion, classifier: 'win'
+    implementation group: 'org.openjfx', name: 'javafx-base', version: javafxVersion, classifier: 'mac'
+    implementation group: 'org.openjfx', name: 'javafx-base', version: javafxVersion, classifier: 'linux'
+    implementation group: 'org.openjfx', name: 'javafx-controls', version: javafxVersion, classifier: 'win'
+    implementation group: 'org.openjfx', name: 'javafx-controls', version: javafxVersion, classifier: 'mac'
+    implementation group: 'org.openjfx', name: 'javafx-controls', version: javafxVersion, classifier: 'linux'
+    implementation group: 'org.openjfx', name: 'javafx-fxml', version: javafxVersion, classifier: 'win'
+    implementation group: 'org.openjfx', name: 'javafx-fxml', version: javafxVersion, classifier: 'mac'
+    implementation group: 'org.openjfx', name: 'javafx-fxml', version: javafxVersion, classifier: 'linux'
+    implementation group: 'org.openjfx', name: 'javafx-graphics', version: javafxVersion, classifier: 'win'
+    implementation group: 'org.openjfx', name: 'javafx-graphics', version: javafxVersion, classifier: 'mac'
+    implementation group: 'org.openjfx', name: 'javafx-graphics', version: javafxVersion, classifier: 'linux'
+    implementation group: 'org.openjfx', name: 'javafx-media', version: javafxVersion, classifier: 'win'
+    implementation group: 'org.openjfx', name: 'javafx-media', version: javafxVersion, classifier: 'mac'
+    implementation group: 'org.openjfx', name: 'javafx-media', version: javafxVersion, classifier: 'linux'
+    implementation group: 'org.openjfx', name: 'javafx-web', version: javafxVersion, classifier: 'win'
+    implementation group: 'org.openjfx', name: 'javafx-web', version: javafxVersion, classifier: 'mac'
+    implementation group: 'org.openjfx', name: 'javafx-web', version: javafxVersion, classifier: 'linux'
 
     implementation group: 'com.fasterxml.jackson.core', name: 'jackson-databind', version: '2.7.0'
     implementation group: 'com.fasterxml.jackson.datatype', name: 'jackson-datatype-jsr310', version: '2.7.4'