I released a new implementation of this using exceptions
rather then returning booleans.

This fixes the last known issues with my implementation by
returning proper xmlrpc fault responses if a header check fails
when using the xmlrpc interface.

I have been testing it over the past week or so on my local
trackers and it seems to be working as intended.

Since it looks like nobody will be able to spend time testing
this I am going to close it as done well enough for now.