Script command, classchange updated to changespr.

Didn't want to just push this without getting some feedback first.

The classchange command is pretty old but isn't used in really anything script wise. changespr is used in official on the new Novice Academy files. How it looks in official:

ChangeSpr "Lumin#nbac01" 4_M_THIEF_RUMIN

So to actually make use of it and remove the 'type' variable I've changed the script command. I changed the naming of it to make more sense and due to the fact that it's so old / not used in anything really.