Changes of Null Object from #2 to #3

Inserted lines at line 2

# [Also Known As|Null Object Also Known As]
# [Motivation|Null Object Motivation]
# [Applicability|Null Object Applicability]
# [Structure|Null Object Structure]
# [Participants|Null Object Participants]
# [Collaborations|Null Object Collaborations]
# [Consequences|Null Object Consequences]
# [Implementation|Null Object Implementation]
# [Sample Code|Null Object Sample Code]
# [Known Uses|Null Object Known Uses]
# [Acknowledgements|Null Object Acknowledgements]
# [References|Null Object References]