[form] fix #719285, due to multiple calls to restore_previous_post, by proper refactorings
* move __init__ code from FieldsForm to Form. Must behaviour here should actually be in the Form base class
* avoid buggy duplicated call to restore_previous_post
* move some code that was in the form renderer to the form'__init__ method (__redirectpath & __form_id hidden input handling))
* 'formvid' should now be specified on form selection, not on form rendering
#!/bin/sh
rm -f web/test/tmpdb*
rm -f web/tali18n.py
rm -f applications/*/test/tmpdb*
rm -f applications/*/tali18n.py
rm -f applications/*/i18n/*_full.po
rm -f applications/*/data/Schema.dot