notification email on student unlinking

sails/src/api/models/License.js

@@ -79,6 +79,8 @@ module.exports = {
   * Formats license number with hyphens
   */
   hyphenize: function (number) {
+    if (!number || number.length < 16)
+      return "";
     var str = number[0] + number[1] + number[2] + number[3] + "-" +
     number[4] + number[5] + number[6] + number[7] + "-" +
     number[8] + number[9] + number[10] + number[11] + "-" +