Bird package

Two additional beaks, insulating Down, and extra bonus Perception.
Nasty stomach hit though.

Renamed Eagle Eyed to reduce confusion, nerfed it a bit (only
half-cumulative with scopes; get Avian Eyes to get the full 30).

Made Mandibles cancel out Fangs & the croc jaws as didn't seem
compatible; categorized Web Walker in Spider, should help boost that a
notch