[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
Schema of the data
------------------
First take a look at the data schema_ then try to remember that you are browsing
through a heap of data by applying stylesheets to the results of queries. This
site is not a content management system with items placed in folders. It is an
interface to a database which applies a view to retreived data.
.. _schema: schema