Add Guard Traits

The GuardUtils can be used now.  The traits are for php >= 5.4 only.
Merge pull request #5365 from texdc/Add_Guard_Traits

[stdlib] Add guard utils and traits
[#5364] Incorporate feedback
[#5364] CS fixes

- Updated copyright year
- Removed unneeded annotations
- Removed empty lines at start and finish of classes
Merge branch 'feature/5364' into develop

Close #5364