nxthemes fragments / widgets (2006-10-17)

I've just committed some code to manage fragment and widget views in the 
theme editor.

* views can be registered by:

- view name / provider name
- engine type
- element type (page, section, cell, fragment, ..)
- model type (e.g. menu item)
- format type (widget, layout, style, ...)

* and fragments are registered by:

- fragment name
- model type

this yields a number of compatible combinations between fragment and 
view types.

The possible combinations are shown in the editor, as in the animation 
http://www.medic.chalmers.se/~jmo/nuxeo5/nxthemes-2006-10-17.html

to test the demo, the HTML code between lines 25 and 33 in   
http://svn.nuxeo.org/trac/nuxeo/browser/NXThemes/NXThemesJsfEditor/trunk/resources/nxthemes/jsf/editor/widgets/page-frame.xml 
must be uncommented first.

the "action fragment" are in .../Nuxeo/branches/nxthemes-fragments

this is meant to encourage component reuse, for instance an "action 
fragment" can be displayed using several widgets (vertical / horizontal 
menu) as long as it provides a "menu item" model type..

Now there are some issues:

- the action service / registry  in NXRuntime returns action links that 
refer to templates on the filesystem (web/incl/breadcrumb.xhtml).
 What is the reason for that?

- some fragments in Nuxeo contain hard-coded id attributes (e.g. <div 
id="nav">).
 And it is impossible under JSF to have two elements on a same page 
with the same id. So a workaround must be used for instance by making 
such widgets addable only once.

/JM