Fix some error handling issues in Window object.
Add better error handling in Window object.

A customized error returns when the user attempts to do an operation
that requires the window to be open when it is not open.
Add IsOpen method to Window object.
Update testing to reflect name changes.
Update some documentation for name changes.
Combine scene package objects.
Fix map initialization bug in Effect object.

How did I not catch this before?
Completely overhaul window management system.

Instead of having the user define a Window object, the object is a
package variable that is managed by Paunch.