improve sqlwall
Merge pull request #503 from cutedemons/master

improve sqlwall
fix parse create table bug
Merge pull request #504 from cutedemons/master

fix parse create table bug
modify version
Merge pull request #505 from cutedemons/master

modify version
fix parse create table bug
Merge pull request #506 from cutedemons/master

fix parse create table bug
fix bug: parse error 'alter table t1 rename to/as t2'
Merge pull request #507 from yakolee/master

fix bug: parse error 'alter table t1 rename to/as t2'
sql wall allow rename table
add test fro sql wall renameTableAllow
bugfix: parse error for 'alter table xx comment 'xx''
Merge pull request #508 from yakolee/master

improve sql parser & sql wall