ENYO-1908: Reduce filetree refreshments after any file operation

Related JIRA: https://enyojs.atlassian.net/browse/ENYO-1908

File ordering method used and DragNDrop feature implies to list file nodes more than once and opened folders of the tree have to be refreshed after any file operations.
Checked on Windows 7 : FF/Chrome/Chrome Canary/Opera/Safari/IE 9 & 10

Ready to be reviewed

Enyo-DCO-1.1-Signed-off-by: Vincent HERILIER vincent.herilier@hp.com