Crystal Adventure new improvments

Hello everyone!

We are doing a lot of playtesting on Crystal Adventures. I have therefore updated the English document with the latest rules. 

In particular, now the Willpower subtracts one when you get 2 Complete Purple Crystals (each time) and I have adjusted the difficulty thresholds of the Quest and Challenge Tests better.

I would also like to add more Character types later on. If you have any suggestions beyond the Warrior, Explorer and Summoner please let me know.

Thank you

Giovanni