Reworked the equation so that you gain a constant cooldown reduction per rank
Additionally all spells can now use all 5 spell points now (though the functionality to have spells that don't follow this rule is still there).
The new variable "cooldown_min" defines (in deciseconds) what the cooldown should be if all 5 spell points are used on it.
For example if you had a 100 charge_max and a 60 cooldown_min, every rank used on that spell would reduce charge_max by 10
Specifics of how the cooldown is affected for each spell has been commented in