Fix open order simulation interactions, when using "trigger once by transaction", it's better to call the script at end of transaction

Some callable are instances with __call__ methods and
ZPublisher already expects them to provide useful func_code & func_defaults.

This is a quick workaround, the main problem is that get_request is monkey
patched to use a completly different implementation in tests, and in some cases
this monkey patch is not properly applied.

Because edit adds a line in workflow_history

Alias properties with storage id are enough, we don't need to declare those
properties.

This tab will also display outcome and expense paths

This way we can reuse this test in projects code

DeliveryLine_init sets a incremental reference for each delivery line, so this
reference cannot be used for searching

A set setter keeps the default value, so in a sense the order is preserved.

Ideally the signature of accessor should be more strict