Merge pull request #583 from yakolee/master

improve sqlwall
1.fix KEY using btree not fit mysql 5.5 syntax,2.fix ALTER TABLE COLLATE bug,3.modify parse error info,like mysql
Merge pull request #585 from yakolee/master

improve sql parser
Merge pull request #587 from yakolee/master

support oracle connect_by_root
fix MySqlSchemaStatVisitor think index as column
Merge pull request #588 from bucketli/master

1.fix KEY using btree not fit mysql 5.5 syntax,2.fix ALTER TABLE COLLATE...
Merge pull request #589 from yakolee/master

bugfix for order by view
with more space ,effect the test. reduce the space
Merge remote-tracking branch 'upstream/master'
Merge pull request #590 from bucketli/master

多加一个空格导致有些测试用例过不去
Merge pull request #597 from yakolee/master

support oracle update/delete/insert hints
support create table ... UNSIGNED ZEROFILL