Improve the plugin manager & the tests
Add flash messenger view helper & tests
Fix namespace constant name
Fix special key "view_helper_config"
Merge branch 'features/port-supermessenger' of git://github.com/blanchonvincent/zf2 into feature/3502

Conflicts:
	library/Zend/View/HelperPluginManager.php
Merge branch 'features/port-supermessenger' of git://github.com/blanchonvincent/zf2 into feature/3502
[#3502] Point flashmessenger to factory class, not implementing class
Merge branch 'feature/3502' into develop

Close #3502