Updated design documentation
Updated design documentation

I clarified and detailed the extension mechanism of DOM elements with enhanced behavior for RIA Widgets.

The Sandbox diagram now features all methods. I renamed setElementFactory/getElementFactory into setFactory/getFactory in the application diagram.

eric-brechemier/lb_js_scalableApp,eric-brechemier/lb_js_scalableApp,eric-brechemier/lb_js_scalableApp