set jquery ajax contentType to default "application/x-www-form-urlencoded; charset=utf-8"
add auto now DateField into IDC Model for testing.
compatible django1.5: use python json module for django1.5
compatible django1.5: ``type`` method frist argument must str not unicode.
compatible django1.5: import LOOKUP_SEP from django.db.models.sql.query not constants