Add "delay" parameter (ms) to spells, for delayed casting.

There are also some tweaks in here for how "target: self" works with a
command block.
Remove weird "update defaults" functionality from back when configs auto-updated.

I think this was breaking some default parameters.
Add "glider" spell. WIP, potentially dangerous!
Remove "delay" as a generic spell parameter, it can cause bad overlapping spell casts.
Add built-in delay to Simulate spell to fix issue with multiple gliders.

Glider fleet!
Update TODO.