Upstream merge Add Session wrapper With this patch we can now use gocqlx like: ``` session.Query(`SELECT * FROM struct_table`, nil).Get(&v) ``` instead of (old format): ``` gocqlx.Query(session.Query(`SELECT * FROM struct_table`), nil).Get(&v) ``` Signed-off-by: Michał Matczuk <michal@scylladb.com>