Uncaught AttributeError: 'QadMapTool' object has no attribute '_QadMapTool__csrRubberBand'


Steps to reproduce
 1. First 
 2. Second 
 3. Third 

```
Traceback (most recent call last):
  File "C:/Users/USER/.qgis2/python/plugins\qad\qad_maptool.py", line 187, in canvasMoveEvent
    self.__csrRubberBand.moveEvent(point)
AttributeError: 'QadMapTool' object has no attribute '_QadMapTool__csrRubberBand'

```
cadtools 0.6.3, QGIS 2.14.18-Essen on Windows 10