[misc] Move the Download (file) button after the New File button to preserve the order from the folder menu.
FILEMAN-45: Hide the orphan file/folder elements when they are empty
* Using chained promises.
FILEMAN-42: Change the root node to act like a folder
* Make sure tree changes are allowed only on regular folder nodes (drive node excluded)
* Prevent the drive node from being dragged
* locationChangeSuccess event can be triggered before the tree is fully loaded