Fix bug in encoding whitespaces introduced with bugfix of #38.

(cherry picked from commit b408f43)

src/main/java/org/dom4j/io/XMLWriter.java

@@ -1662,7 +1662,7 @@ protected String escapeElementEntities(String text) {
                 case '\r':
                     // don't encode standard whitespace characters
                     if (preserve) {
-                        entity = String.valueOf(c);
+                        entity = String.valueOf((char) c);
                     }
                     break;