Add RulebookPeer to Windows build.
Fix registered name for RulebookPeer.
Properly log track header errors when loading.
Exclude old Win32-specific files from build.

NetworkSession will probably be revived, but the others are just kept
around as a reference until we can replace them.
TrackList now deals in TrackEntryPtrs.

This is so the TrackEntry can live past the lifetime of the TrackList
(e.g., in a Rulebook).
Add OpenTrack(TrackEntryPtr).

This is a convenience overload for when you've already got a
TrackEntryPtr and not just the name of the track.
Rulebooks are now reusable.

This makes them easier to extend via Lua by having a default
constructor, and a full TrackEntry is provided in case the Rulebook
wants to do any specific processing based on the extra metadata.