Added various symbol groups from other mods to improve compatibility

Re-coded Bounty Hunter and Wanted Poster to use "hunted" group. I don't have any specific plans to put this group in other mods, but this change should make things easier for any other modder who wants to issue bounties. Now you can mark this mod as required DLC (or copy my scripts) and simply add the group to the desired symbol.

Added "giraffelikes" group to Orange for compatibility with upcoming Autistic Pride Pack

Removed the "when destroyed" requirement from Wanted Poster to match the version 0.14 update

- Fixed a bug where Horse wasn't affected by Checkered Flag the first spin it appears

- Remade the internal code of Emu to enable cross-mod compatibility (now uses group "emulikes")

- Added Horse to the list of symbols buffed by Farmer, for flavor reasons per Invenio's suggestion

- It can feel like a bit of a rip-off that Emu's payout for a Bounty Hunter is less than what a Bounty Hunter gives for Thieves and Outlaws. So I added an extra 5 coins specifically when Emu kills Bounty Hunter, for a total of 20. Oranges and Shiny Pebbles are still worth only 15.

Fixed a bug where Zaroff's Contract had no effect