ResultSet wrapper for RowData

With result set wrapper (scalikejdbc.async.internal.RowDataResultSet) one can use typeclasses in getters for conversion from predefined types to a domain types (see scalikejdbc.TypeBinder)
Also it makes usage of scalikejdbc.async.internal.AsyncResultSetImpl more consistent with sync version (scalikejdbc.WrappedResultSet), i.e. one can use rs.get[Int]("columnName") instead of changing it to rs.int("columnName").
ResultSet defined in this pull request has same restrictions as scalikejdbc.async.internal.AsyncResultSetImpl (i.e. it raises usupported exception for getters of complex type, etc.)
See example of usage in sample.AsyncLover#apply