intro/discovery/discovery rid out of Xorm

[vidya88]

@logrusorgru commented on Apr 18, 2018

The xorm drops (*xorm.Rows).Next() error and (*xorm.Rows).Err() can only returns sql.ErrNoRows. Since, CXO have a little SLQ work, then I think CXO should rid out of the xorm to

• avoid unnecessary dependency
• handle possible error

The work is faster then time of waiting reply from xorm developers.

Work: 50% (in progress, next after #147)
Test: 0%