Don't send repeated position/speed commands to the launch

[qdot]

If a duplicate speed/position command has been sent to the fleshlight launch, drop it and respond to the client with ok.

Note that both speed and position need to match. We may want to continue to the same position as a higher speed in the same transfer, so those would be two different commands.

Uncomment test in FleshlightLaunchTests.cs when this is done.