Support new path pattern: 0 or more layers

[guoguan...@qq.com.INVALID]

Hi guys!
     Now IoTDB supports the following path patterns:
* (1 asterisk) - one layer
** (2 asterisks) - one or more layers

   We need to support a new path pattern: 0 or one or more layers, there are 
some optional schemes:
       Scheme 1, support it directly with a specific syntax:
          *** (3 asterisks) -  0 or one or more layers

       Scheme 2, use more common syntax:
 a special symbol (such as $, or someone else) - 0 or 1 layer
$* - 0 or 1 or more layers

     JIRA:   https://issues.apache.org/jira/browse/IOTDB-3450

    Any ideas?



guoguan...@qq.com