expose remoteTransportRevision

[mdavidsaver]

Right now nothing is done with the peer's reported protocol version number. Transport.getRevision() is always returning PVAConstants.PVA_PROTOCOL_REVISION when it should be returning the lesser of this or remoteTransportRevision.

So far, monitor flow control messages have been conditional on a pvRequest option 'record._options.pipeline'.
This requires the client to implicitly know if the server supports this protocol feature.
I'm planning to make monitor flow control messages mandatory, and to use a minor version increment to signal this in a backwards compatible way.

[ralphlange]

Copied over issue to its new place.
Closing.