allow leap second in ISO 8601 Timestamp

Also clarify in testing that we require unambiguous time zones (SHOULD*
requirement)

Author: milt

spec/cljx/xapi_schema/schemata/json_spec.cljx

@@ -123,8 +123,11 @@
  (it "is a valid ISO 8601 DateTime"
      (should-satisfy+ Timestamp
                       "2014-09-10T14:12:05Z"
+                      "2015-06-30T23:59:60Z" ;; leap second
                       :bad
-                      "09-10-2014T14:12:00+500")))
+                      "09-10-2014T14:12:00+500"
+                      "2014-09-12T03:47:40" ;; no time zone
+                      )))
 (describe
  "Duration"
  (it "is a valid ISO 8601 Duration"

src/cljx/xapi_schema/schemata/regex.cljx

@@ -22,7 +22,7 @@
   #"[0-9A-Za-z]{8}-[0-9A-Za-z]{4}-4[0-9A-Za-z]{3}-[89ABab][0-9A-Za-z]{3}-[0-9A-Za-z]{12}")
 
 (def TimestampRegEx
-  #"^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-2])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24\:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$")
+  #"^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-2])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24\:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)|T23:59:60Z)?)?$")
 
 (def xAPIVersionRegEx
   #"^1\.0\.(\d+)?$")