Discarded quaternions explainer (Patreon)

This was my original (buggy, incomplete) attempt at the upcoming quaternions video. I've since restarted it about 5 times aiming to simplify it and abstract some useless information. 

I've now decided to keep the mathy side of it to a minimal and explain how to actually use quaternions and what to look out for. Anyway, thought you might enjoy this unpolished, discarded version.