Added getAndForget method to Session\Store.

Added method to Seesion\Store as detailed in issue #4135.
Added @return to getAndForget in Session\Store
Rename getAndForget method to once.
Merge branch 'feature/sessionGetAndForget' of https://github.com/Garbee/framework into Garbee-feature/sessionGetAndForget
rename method. update change log.