Customizable RC car battery post

Fully parametric (customizable) battery post for RC cars.

2018-05-19: added cross base version.

Parameters

 POST_DIAMETER,POST_HEIGHT = diameter and height of the cylinder.  
 BASE_WIDTH,BASE_HEIGHT = base width (excluding cylinder base) and height.  
 SCREW_DIAMETER, SCREW_LENGTH = diameter and length of mounting screw.  
 PIN_DIAMETER = diameter of the pin hole.  
 PIN_STEPPING = distance between pin holes.  
 CROSS_WIDTH, CROSS_HEIGHT, CROSS_THICKNESS = parameters for cross talus.