Updated vrsent to the latest version.
Use node.locked_by_me property.
Implemented locking of object by selecting them.

* When object is locked by some other clinet, then
  it can not be selected.
* When user does not have permission to select write
  to the node, then it can not select coresponding
  blender object.
* When object is locked by current Blender, then the
  bounding box is green.
* When object is locked by other Blender, then the bb
  is red.