get_uint_index
Description:
Gets the value that is at the given index for the given tag in the given list.
Parameters:
| this | 
           a TagList to get the tag from  | 
      
| tag | 
           tag to read out  | 
      
| index | 
           number of entry to read out  | 
      
| value | 
           location for the result  | 
      
Returns:
| 
           true, if a value was copied, false if the tag didn't exist in the given list.  |