LCB store callback confuses cas and token

the js side of the lcb store callback expects a triple of (err, cas, token) the js callback expects (err, cas, token) https://github.com/couchbase/couchnode/blob/3d0b7e8ef249ac2c912845320e5742b6fa6ff197/lib/collection.js#L473
but the LCB side only writes (err, token) and omits the cas.. now the token is treated as the cas.

https://github.com/couchbase/couchnode/blob/master/src/connection_callbacks.cpp#L168