Allow to run multiple instances of zfcuser
Merge pull request #256 from Freeaqingme/dynamicly

Allow to run multiple instances of zfcuser
Allow setting of custom user hydrator and user mapper from config file.

Allow setting of custom user hydrator and user mapper from config file.

Updated README.md to include the 'user_mapper_class' and 'user_hydrator_class' config options.
Extracted the creation of the User Entity into a separate ServiceManager entry, for easier overriding.