"Change file permissions" context menu item

[AlexWayfer]

Summary

Context menu item like "Change file permissions" and pop-up for this.

Motivation

When I create a file from tree-view, sometimes it should be executable file, so I want to select another context menu item and change its permissions right from Atom.

Describe alternatives you've considered

• Switching to terminal and chmod.
• chmod package (doesn't work somewhy).