add initial CommandInterface
add register_claim and ignore_last_command
add first command_interface PATCH test
make command_interface.t use TestWebServer

There's no need for this test to lean on the real webserver, plus we can
test that the requests it's generating more thoroughly.
check headers on register and activate
finish status update methods
add renew_claim
do NOT return http response watcher

This could lead to sublte bugs if client code keeps a reference to it
around, yet the CommandInterface wants to delete the watcher.
add tests for CI notify/callbacks
http responses go to the same EG callback
delete_timer returns 1
use events based on http status codes
sort mock command_interface methods
add specific timer methods to CommandInterface
bugfix:  don't rely on unique memory addresses

When creating and destroying many state machine factories (such as
during testing) the same memory address could be reused for states.

This was a problem because we were relying on that being unique when
creating semi-anonymous state classes.
add EventGenerator
set update_url on http 201/202
rename ignore_last_command to abandon_last_request
remove unused dependency
add backoff to retry and activate