ENYO-2270: Added trace to display the src url of the Designer iframe

Enyo-DCO-1.1-Signed-off-by: Yves Del Medico <yves.del-medico@hp.com>
ENYO-2270: Trap exception while rendering a kind in the Designer and raise an error message

Enyo-DCO-1.1-Signed-off-by: Yves Del Medico <yves.del-medico@hp.com>