Add Chain authentication storage class. The Chain storage can be used to
chain multiple storages together.
Replaced tabs by spaces.
Add tests for Chain storage engine.
Use correct plural of `storage`.
Refactored isEmpty loop to be more readible.
Renamed storageQueue to storageChain.
Use PSR-2 as coding style.
Merge branch 'feature/authentication-chain-storage' of git://github.com/roelvanduijnhoven/zf2 into feature/2718
[#2718] CS fixes

- Remove leading/trailing space inside method argument lists.
Merge branch 'feature/2718' into develop

Close #2718