PloneFormMailer to PloneFormGen Migration (under construction)

@jone @phgross @senny hey there, here is my pfm2pfg migration branch.

Its a blueprint to migrate ploneformmailer to ploneformgen.

Please take a look at the base concept with utilities, objects and blueprint.

Following things are missing:

- tests
- PfmXMLHandler refactoring: there is a little ghetto with the methods. I'll improve this with the tests
- a lot of comments
- some adjustments for each formfield for correct migration