developer-level changes Silva 1.2

Hi there,

This is the developer-level changes document for Silva 1.2, describing 
differences from Silva 1.1 and earlier versions:

 From 1.1 to 1.2:

* the 'action_paste' and 'action_paste_to_ghost' methods on Folder have
   a new signature, instead of returning a list of messages it now
   returns (message_type, messages) where message_type can be 'feedback'
   and 'error' and messages is the list that used to be returned.

* tab_edit for VersionedContent views has changed to make use of a new
   macro, ``macro_tab_edit/macros/editor``, instead of
   ``macro_index/macros/master`` directly. ``macro_tab_edit`` does use
   ``macro_index`` indirectly.

   A default tab_edit is supplied in VersionedContent views.
   SilvaDocument however overrides this with its own tab_edit.
   You can also do in your own product.

   The following slots are available in ``macro_tab_edit/macros/editor``:

     * editor_css - add in editor-specific CSS stylesheets.

     * editor_refresher - a slot to put in special refreshing code for
       editors that are sensitive to Zope session timeouts, such as the
       forms editor.

     * editor_selection - add extra fields above the main editor content
       area to allow the user to switch editors, such as between kupu and
       the forms editor.

     * editor_content - the main editor content area, showing for
       instance the forms editor or kupu.

* The public view directory layout changed due to some change in the way
   we register views. For some functionality on the
   VersionManagementAdapter, we needed to get a rendered version, which
   wasn't allowed the way the views were previously set up (fetching the
   version happened in the render scripts, each script would render a
   specific version).

   Changes:

     * instead of registering a 'public' view for VersionedContent
       objects, they are now registered for Version objects, the view
       assumes

     * instead of 2 scripts 'render_view' and 'render_preview' only
       'render' is called for both view and preview, if you want to
       make a distinction between the two, you can register a new
       view_type called 'preview' to another subdirectory and place a
       'render' script in that, the general pattern is that if you want
       to use only 1 script you place it directly in the
       'public/<meta_type>' directory, if you want to have seperate
       scripts for view and preview, create a 'view' and 'preview'
       directory in that dir ('public/<meta_type>/view' and
       'public/<meta_type>/preview')

     * the 'model' variable in the render script does not point to the
       VersionedContent object anymore, but instead it refers to the
       Version object (of course it still refers to the object itself
       in case the object is not of a versioned type)

Let us know if anything is unclear!

Regards,

Martijn