Reinitialisation of form fields while validation to get relevant fields

[toirl]

Formbar needs to initialise the fields twice when doing a validation:

1. The first run is when first loading the form. All fields are build
2. The second run is on validation. Formbar now checks which fields based on the condionals of the form are relevant for validation. Currently the only way to check this is to reinit (redo step 1) the fields and evaluate all rules while collecting the fields.

This is not well implemented and seems to be not necessary. Further this might cause performance issues but in some tests a form with may rules the seconds run doesn't take to much time:

To show the relative difference: ~4seconds for both calls and ~3.6 seconds with only the first.