Added Primal Transformation Spell for Mouse Druids

In what was a grave oversight on my part, I realised that I did not include a core druid ability in the initial release - animal transformation!

That has been rectified now with the Primal Transformation spell. With this spell, you transform into another creature for [LEVEL] + [DICE] hours. You increase your damage, HP and attributes based on the creature you transform into and gain additional effects along with it. There is a d6 table for creatures (see above), adding some randomisation into which animal you transform into and encouraging players to use all three dice when activating it.

The recharge requirement for the spell is to "Consistently act like a different creature for 2 days" - it is my sincere hope that GMs enforce this and make players actually act like an animal for 2 days of in-game time.