Encode ':' in filterFn hashing in a safer way
Several major fixes for filters:

- Bundle filters even when they aren't pointed to by an explicit ref.
- Add TransformBuilder#model() to get a lazily created scoped model.
- Handle bundled dynamic filter parameters in form {$ref: pathToDependencyRef}
  on fresh page load, appropriately.
- Modify mutator listener on filter dynamic parameter dependencies, so that we
  can clean the listeners up. Then, clean them up via Model 'cleanup' event.