Seperated configs and updated system

* New configs "spells.yml", "cooldown.yml"
* Added two CustomConfig classes SpellConfig, CooldownConfig
* Updated references
* Fixed few javadoc annotations
Updated commands to support new config system

* Allowed the editing of "cooldown.yml", "spells.yml" using commands
* Updated reference for SpellList (Forgot to on last commit)
* Updated us-english.properties