Fix the start script for windows.

Author: mocobeta

luke.bat

@@ -1,2 +1,5 @@
-if not "%JFX_HOME%" == "" JAVA_OPTIONS=--module-path %JFX_HOME\lib --add-modules=javafx.controls,javafx.fxml
-start javaw %JAVA_OPTIONS% -jar .\target\luke-javafx-with-deps.jar
+@echo off
+if not "%JFX_HOME%" == "" (
+    set JAVA_OPTIONS=--module-path %JFX_HOME%\lib --add-modules=javafx.controls,javafx.fxml
+)
+start javaw %JAVA_OPTIONS% -jar .\target\luke-javafx-with-deps.jar