Refactor Error Handling / Instance changes

[awilliamson]

Whilst doing other work I looked through the existing code for error handling. The interactions between entities, instance, and the SF Core is messy to put it lightly.

A refactoring would improve the ability to trace these errors, and improve tracebacks. Some Entity methods mimic Instance functions in their entirety with no real reason or added benefit.

I feel that Core, Instance, and Entity are far too tightly coupled/intertwined. This would be an ideal opportunity to do the Instance changes we've been planning. Make the Core focus on the Instance, with the Entity being a physical 'shell' for the SF Code. Have a clear categorisation of errors in zones, for the core, instance errors ( libs etc ), and SF code space all to be handled in a single easy-to-access location.

At the moment we have multiple pathways for erroring out, and multiple versions of functions which essentially do the same erroring task. Some cleanup after themselves, some are just warnings, over-time this haphazard erroring style has lead to superfluous calls and messy interaction and chaining; this needs to be cleaned up. Strict zoning and procedure should improve how contributors create code with error handling, and make for a better model for people wishing to understand how it works.