ENYO-2774: raise an alert if enyo is too old in designer frame

* ENYO-2774: raise an alert if enyo is too old... (HEAD, origin/ENYO-2774, ENYO-2774)
* ENYO-2752: added bug trap
* ENYO-2746: test attribute before checking its content

Enyo-DCO-1.1-Signed-off-by: Dominique Dumont <dominique.dumont@hp.com>