Fixed Little Little Horn bug

Fixed a bug that caused my custom familiars to not appear for characters other than Siren

Added Little Little Horn and Poo Bum to the item pool.

Added 3 captures for bosses from the new familiar pool:
1) Blastocyst = Mystery Egg (Suggestion by Meman82)
2) Stain = Jaw Bone
3) Cage = Lil Spewer

Added the Little Harbingers as a capture for the Horsemen, and used Buddy In a Box as a placeholder for other bosses.

Updates Little Little Horn to target non-converted enemies before converted ones.

Adds Little Little Horn familiar.

Added Leech as a familiar for Pin and variants.

Changed boss charming logic slightly, and gave Siren natural Charm Shots.

Just changing the thumbnail and adding the familiars tag.