ENYO-3574: Change selection and drop target enlightment in designer with a tranparent and animated overlay

Related JIRA: https://enyojs.atlassian.net/browse/ENYO-3574

Selection and drop target enlightment in designer are now realized from an animated and tranparent overlay

Enyo-DCO-1.1-Signed-off-by: Vincent HERILIER vincent.herilier@hp.com