Feature/fix tests (#34)

* feat: Java 11 -> Java 17

* feat: XSL cleanup removed.

* feat: fixing unit tests.

* feat: formatting + tabs -> spaces.

* feat: fixing unit tests.

Author: grigoriev

src/main/java/org/outerj/daisy/diff/HtmlCleaner.java

@@ -104,8 +104,6 @@ public String toString() {
     }
 
     private String clean(String s) {
-        return s.replaceAll("\n", "").replaceAll("\r", "").replaceAll("<",
-                        "&lt;").replaceAll(">", "&gt;").replaceAll("'", "&#39;")
-                .replaceAll("\"", "&#34;");
+        return s.replaceAll("\\n|\\r", "");
     }
 }