Remove an unused method

airsonic-main/src/main/java/org/airsonic/player/util/StringUtil.java

@@ -255,15 +255,6 @@ public final class StringUtil {
                 .toArray();
     }
 
-    /**
-     * Determines whether a is equal to b, taking null into account.
-     *
-     * @return Whether a and b are equal, or both null.
-     */
-    public static boolean isEqual(Object a, Object b) {
-        return Objects.equals(a, b);
-    }
-
     /**
      * Parses a locale from the given string.
      *