Bug #0000268: Code Cleanup in 5.2.x branch
- ability to override every system class, that is retrieved via factory (e.g. kEventManager)
- all classes are created via kFactory class, so they can be overridden too
- system object, like kUnitConfigReader class object are no longer stored in kFactory class
- class registration in kApplication::RegisterDefaultClasses method rearranged into logical groups
- design patterns, noted in class/method comments, when applicatable
- unit config re-reading redesign by interface usage
INP-224
