Primary video now affects the mouse the same way it does in the original game: the cursor gets moved to a set location when starting a conversation, and is blocked from moving above a certain threshold. Also removed the static pointer from PlayPrimaryVideoChan0.
When exiting a scene while holding an item, the cursor shown is now the fourth version of the item cursor, just as it is in the original engine. When entering a scene through the map while holding an item, the cursor no longer gets reset to the default one.
Made all states (Scene, Credits, Help, etc.) singletons, as well as subclasses of a common State parent with a proper state switching API. Moved the OnPause virtual function from RenderObject to ActionRecord and hooked it into the state switching code. Also got rid of the NancyEngine pointer that got passed around between most classes, and replaced it with several convenience macros. As a result of these changes action records that render to the viewport no longer disappear after opening the menu, and state changes feel snappier.
Rewrote most of the engine using a much more object-oriented approach and using more of ScummVM's common classes. This design deviates quite a lot from the original engine's, but should be more maintainable and extensible in the future.
