Changes to notice compiler for interps

* Interps are sometimes added as "Add 22(b) and paragraphs 1, 2", which causes duplicate POSTs (as 22(b) contains 1 and 2). Account for that by removing duplicates
* Interpretations for 22(b) might be added *after* 22(b)(1), but adding 22(b)(1) would have created a skeleton for 22(b). Replace these "placeholder" nodes
* From time to time, the *same* interpretation header is added by separate notices
* Don't crash when trying to delete a node that doesn't exist; log a warning instead
* The fail safe of adding empty nodes now uses proper node type
* Replace "move then edit" amendments with "delete then add" amendments - this makes compilation work better
* Limit changes to the current reg
* (Unrelated) Patch out calls to requests when testing the image layer. This prevents the testing framework from making superfluous HTTP requests
* (The Kicker) Turn on interp processing for amendments