Move models from common to cms.

Add unit tests.

common/djangoapps/util/converters.py

@@ -10,12 +10,12 @@ def time_to_date(time_obj):
 
 def jsdate_to_time(field):
     """
-    Convert a true universal time (msec since epoch) from a string to a time obj
+    Convert a universal time (iso format) or msec since epoch to a time obj
     """
     if field is None:
         return field
-    elif isinstance(field, unicode):  # iso format but ignores time zone assuming it's Z
-        d=datetime.datetime(*map(int, re.split('[^\d]', field)[:-1]))  
+    elif isinstance(field, unicode) or isinstance(field, str):  # iso format but ignores time zone assuming it's Z
+        d=datetime.datetime(*map(int, re.split('[^\d]', field)[:6])) # stop after seconds. Debatable  
         return d.utctimetuple()
-    elif isinstance(field, int):
+    elif isinstance(field, int) or isinstance(field, float):
         return time.gmtime(field / 1000)