Performance config

[calebmsword]

• A new performanceConfig property can be provided to the options hash passed to cloneDeep/cloneDeepFully/etc.
• The ability to perform default or robust type-checking has been implemented.
• The ability to ignore extensibility/frozenness/sealedness has been implemented (it has marginal performance improvements).
• Tests have been refactored to reduce excessive indentation and to make assertions more declarative.