Made mandatory email property in create_user optional and provide a 'best guess' if not passed

Removed update_user from class Server

Added _update to class User as method for setting the user properties

Added setter methods for user.name, user.email, user.fullname and user.active

Added hook_store to class Server with basic functionality

Added unhook_store to class Server with basic functionality

Fixed the INACTIVE_USER constant and renamed it to NONACTIVE_USER as in the ECDefs.h