Improve Mixins class

[Sv443]

• Add modification context chain (list of prior mixins that were applied and optional identification context)
• "Interrupt" system where functions can be added to dynamically interject after a condition matches when a certain mixin has been applied, offering an alternative path to coordinating consistent priority values between all mixin suppliers
• Populate context object with some props by default: initialValue, priorMixins, mixinsRemaining, config