Specify recursion depth

[replygirl]

• In individual functions and static methods of CasedObject, the user can specify depth in a second options argument (overlap with Support options for change-case #8 & Make recursion optional, defaulting to true #9)
• When initializing CasedObject, the user can specify depth in options, which is stored in private _options (overlap with Support options for change-case #8 & Make recursion optional, defaulting to true #9)
• When interacting with a CasedObject instance, the user can get & set private _options through options (overlap with Support options for change-case #8 & Make recursion optional, defaulting to true #9)