Set encoding to utf-8 (#407)

* Updated clean script for Windows

* Changed UTF-8 to utf-8

Author: wfouche

tulip-runtime/src/main/java/io/github/tulipltt/tulip/api/TulipApi.java

@@ -48,7 +48,7 @@ public class TulipApi implements Callable<Integer> {
     public static String runTulip(String text, TulipUserFactory userFactory) {
         // Record the start time in nanoseconds
         long startTime = System.nanoTime();
-        System.setProperty("python.console.encoding", "UTF-8");
+        System.setProperty("python.console.encoding", "utf-8");
         String outputFilename = TulipKt.initConfig(text);
         TulipKt.runBenchmarks(userFactory);
         // createHtmlReport(outputFilename, text);