Synchronize memoized resource getter

source/net/filebot/Resource.java

@@ -32,11 +32,13 @@ class MemoizedResource<R> implements Resource<R> {
 
 	@Override
 	public R get() throws Exception {
+		synchronized (resource) {
 			if (value == null) {
 				value = resource.get();
 			}
 			return value;
 		}
+	}
 }
 
 class TransformedResource<R, T> implements Resource<T> {