ENYO-2899, ENYO-2074, ENYO-1503, ENYO-1768: enable generation & usage of minified apps

* ENYO-2899, ENYO-2074, ENYO-1503, ENYO-1768: adapt to new Enyo (HEAD, origin/ENYO-2899, ENYO-2899)
* ENYO-2899: take into account comments by @graynorton & @unwiredben (enable to use enyo/HEAD)

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>