Added main javafx class

Pull the add-javafx branch and make sure it works properly.

src/ui/main.fxml

+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.layout.*?>
+
+<AnchorPane xmlns="http://javafx.com/javafx"
+            xmlns:fx="http://javafx.com/fxml"
+            fx:controller="Main"
+            prefHeight="400.0" prefWidth="600.0">
+</AnchorPane>