Add the ability for jutsus to linger after cast.

This should allow for enhancements to the water bullet being able to be fired after. As well as for things like a substitution to know you are still in the time window for taking a hit and it triggering or ending the cooldown.

May be good to tie this in with the cooldown system though store more info such as casts left. Though you wont need to store these between saves. If a player leaves just deactivate it.