Started writing the dendrite library

The dendrite library defines structures meant to streamline the writing of adventure games.
Added the Interactable base type

Everything in dendrite is in someway interactable or defines how an interaction
occurs.
Added Event and Interaction templates

These templates are ways to take advantage of the unordered nature of the
expert system to define interactions between objects and events that are raised
in response to something happening.
Added the Item class

This class is the base class of all things that can be added to an inventory
Added the Entity type

This is an interactable thing that contains an inventory
Added the Player type
LoadEngine.clp: Added automatic loading of the dendrite library
Interactable.clp: Added a description slot and associate message handler

The message handler prints the description out to the screen