Consider moving error-handler into the core framework

[ben-ryder]

Package Information: kangojs, error-handler

Describe your improvement
It's likely that the error handler (or a version of it) will be used on every project using KangoJS, so why not just move this functionality to the base framework or at least add some functionality like I have for request auth/validation to make this less custom/external to the framework.

Is your suggestion related to any problems?
Reduces boilerplate and repeated code, error handling will probably rely on dependency injection so it makes sense to possibly absorb the functionality

Additional context
n/a