Added Rooms as places the player can occupy and travel between.

Created new myst_adventure script.  This script is in charge of initializing rooms and the connections between them.  It also initializes objects within those rooms, sets the player in their starting room, and starts the adventure.

The GO command will now move players between rooms, as well as LOOK at the room the first time they visit.

The LOOK command will now display the description of the current room when no objects are specified.