ZmtLaunchPlugin.java: working directory can be set via project property

src/main/groovy/de/zmt/gradle/ZmtLaunchPlugin.groovy

@@ -94,9 +94,12 @@ public class ZmtLaunchPlugin implements Plugin<Project> {
         
         run {
             description = description + ". Arguments can be supplied via 'args' project property (-Pargs='<args>')."
-            if(project.hasProperty('args')){
+            if (project.has('args')) {
                 args(project.args.split())
             }
+            if (project.has('workingDir')) {
+                workingDir = project.workingDir
+            }
         }
     }