Merge pull request #51 from opencloudb/master

fix reload bug
change cmd to volatile ,maybe changed and can't see
1、druidparser支持无表的select语句，如select 1或select 1 union select2
2、druidparser增加几种测试用例：无表select语句、批量insert、insert ...on duplicate key update ...、
Merge pull request #52 from wdw1206/master

1、druidparser支持无表的select语句，如select 1或select 1 union select2
Merge remote-tracking branch 'origin/master'