title: Sqlalchemy insert query does not return results
body: <p>I have tried to select returning values from insert query:</p>
  
  <pre><code>HOST_INSERT_QUERY = (
      Host.__table__.insert()
          .values(
              name=bindparam("name"),
              source=bindparam("source"),
              type=bindparam("type")
                  )
          .returning(Host.__table__.c.id)
  )
  result = db_conn.execute(HOST_INSERT_QUERY, values)
  </code></pre>
  
  <p>What I see from db.echo:</p>
  
  <pre><code>info sqlalchemy.engine.base.Engine INSERT INTO hosts (name, source, type) VALUES ( %(name)s, %(source)s, %(type)s) RETURNING hosts.id
  info sqlalchemy.engine.base.Engine ({ 'name': 'hhh', 'source': '["import"]', 'type': 'host'},{...})
  debug:  Added 2 hosts
  </code></pre>
  
  <p>It really works. Hosts inserts into database, but I see some troubles in debugger; result (ResultProxy) has:</p>
  
  <pre><code>rowcount = 2 #right!
  is_insert = True #right!
  return_rows=False #WHYYYY????????
  </code></pre>
  
  <p>If I try to:</p>
  
  <pre><code>result.fetсhall()
  
  AttributeError: 'ResultProxy' object has no attribute 'fetсhall'
  </code></pre>
  
  <p>Versions:</p>
  
  <ul>
  <li>SQLAlchemy 1.3.1</li>
  <li>psycopg-binary 2.7.7</li>
  </ul>
  
  <p>Note!
  This code only works when inserting a single record. When inserting multiple lines, it is not possible to pull the values ​​out of the RETURNING.</p>