isSubclass(classValue) {
			return (typeof(classValue) == 'function' && classValue.prototype instanceof this);
		}
Checks whether the given class value is a subclass of this class.

@memberof LuCI.baseclass

@param {LuCI.baseclass} classValue
The class object to test.

@returns {boolean}
Returns `true` when the given `classValue` is a subclass of this
class or `false` if the given value is not a valid class or not
a subclass of this class'.