The button does seem to appear in the demo page.
The button seems to be created where it supposed to be.
fastUi actually creates the elements its supposed to create.
Use the widget definition instead of simple javascript objects.
Added namespace UI support instead of ui-* prefixes for attributes.
Adding ui:config works for the most part.
Creating elements inside other elements works good.
Added a bunch of documentation, use ui:srcNode instead of ui:src, changed the default type to ui:config elements to js instead of ui.