Wizard projectile fixing

Created by: ComicIronic

Should fix Bump being called when colliding with other projectiles. Fixes #3002 (closed). Magic missile should now disappear properly. Fixes #2996 (closed), reopen if it's still happening. Added a message to magic missile popping so it's a bit more obvious. All spell projectiles now delete after casting, which is good and should fix any issues.

In the pipeline: making casting a verb or UI icon, and making spells datums instead of AMs.