Making it a little easier to re-use an existing session object

I've updated the constructors in both classes to use type-hinting to force a SessionInterface and added a setSession() method to both. If provided, it will use the passed SessionInterface, else it will define a new session as you already had it.

Sorry for all the white-space updates. NetBeans auto-formatted and I didn't realize it. You didn't need all the trailing whitespace anyway, amiright?