Pass in overridable options to child spawners

[Petraea]

Hi there,
In addition to the profile defaults, it is occasionally handy to be able to set up user-editable fields in the ProfilesSpawner option form. To do this, the config has to be passed in from the form itself (and optionally overidden by values in the profile).

[mbmilligan]

Hi, thanks for the contribution!

I'm sorry to say, I'm having trouble understanding exactly how this change works. Can you tell me a little more about your use case and how you are implementing it? For one thing, I presume you are overriding the form creation at some point, since presently it doesn't generate editable form fields. I'm trying to reason about the effect of making options_from_form() have side-effects when it didn't before, and that would be easier with a concrete example of the sort of form data you are generating.