Handle natural 1s and 20s on spell check rolls

[algnc]

Checking for natural 1s on spell rolls would indicate when corruption or a misfire occured. it could also check for natural 20s to add double caster level.

edit: actually, I see now you get a red number on a 1. That should work. Natural 20 could double caster level which would be nice.

[mooped]

Updated title to reflect the edit.

[mooped]

Likewise we should handle natural 1s which seem to be another special case.

[cyface]

@algnc can you validate this one in preview-0.24?

[algnc]

both fumble and crit roll and total their rolls correctly now!