Made playground automatically run

Author: aure

Playgrounds/Hello World.playground/contents.xcplayground

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<playground version='5.0' target-platform='ios' buildActiveScheme='true' importAppTypes='true'>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true' executeOnSourceChanges='true' importAppTypes='true'>
     <timeline fileName='timeline.xctimeline'/>
 </playground>