Introduces base class and interface for the factories

Created by: stefanoborini

Introduces a base class for the factories.

Fixes #49 (closed)

force_bdss/ui_hooks/base_ui_hooks_factory.py

 import logging
 from traits.api import provides, Type
-from envisage.plugin import Plugin
 
 from force_bdss.core.base_factory import BaseFactory
 from force_bdss.ui_hooks.base_ui_hooks_manager import BaseUIHooksManager