ZF2-396: Add custom params to flash messanger messages

Description

To use messenger seamlessly with I18N, one would need to separate variables from message (translation key) for transportation and assemble just in time for translation in view layer.

So there is NO need to translate within controller before adding message to messenger.

Comments

This issue has been closed on Jira and moved to GitHub for issue tracking. To continue following the resolution of this issues, please visit: https://github.com/zendframework/zf2/issues/2501