ENYO-3570: change default folder node opening behaviour
Revert "ENYO-3570: change default folder node opening behaviour"

This reverts commit 494375e381ad5f328cf2aaff9e11fdc734088db6.
ENYO-3570: Double-click on folder node label does open it too
ENYO-3570: remove dead code
ENYO-3570: compact code
ENYO-3570: change folded/unfolded assets for the filetree
Merge pull request #676 from enyojs/ENYO-3570

ENYO-3570: change folder nodes opening behaviour

LGTM + Works fine.