code: func (c *configuration) pop() head {
  	retVal := c.stack[len(c.stack)-1]
  	c.stack = c.stack[0 : len(c.stack)-1]
  	return retVal
  }
docs: /*  stack machinations */
  // pop pops the stack. It isn't really used any more. removeStack(), removeTopStack() and removeSecondTopStack() has superseded its function