added mouse selection of abilities to the ability menu
Added in the improvements system. Abilities can be assigned a list of Improvement ScriptableObjects that define which fields of the ability can have their values altered to improve the attributes of the ability. Only numerical fields can be modified for now and there is no restriction on modification
Added the Improvements system to all current abilities. The explosionSize attribute was added to CloseBlast abilities so that the size of their blast can be altered. The way the scaling is applied can be changed by overriding scaleBlast