Enyo 2517: Clarified and fixed preview screen size

* ENYO-2517: rework left panel to clarify DPR effects on screen size 
* ENYO-2517: fix indentation
* ENYO-2501: fix size typos in display definition

Enyo-DCO-1.1-Signed-off-by: Dominique Dumont <dominique.dumont@hp.com>