New API version

This API update contains new stuff, here's what new:

Adds BaldiTVExtensionHandler class, which is the static class used for the new Baldi TV system (along with BaldiTVCharacter and SimpleBaldiTVCharacter)

Adds NPCBuilder<T>.IgnorePlayerVisibility()

Fixes using existing enums for items and npcs giving warnings

Adds new Unobtainable ItemFlag, used to dictate items that should never be given to the player or be instantiated.

Adds EnumWithExtendedNameExists<T>(string name)

Moves currently unused Runtime ItemFlag to 128

So mostly about Baldi TV System, nice MTM101!