Meduce bow attachment node and engine shroud

[DenisDanilov]

As instructed on the KSP forum, I am bringing the feature requests here.

As the Medusa engine is a) unusable during launch, b) quite big and heavy and c) rather compact when stowed in comparison with the classic Orion, it would only be natural to launch a Medusa sailer upside-down, with a conventional rocket stage mounted immediately under the heaviest part.

And as we have no non-Orion 5 m rocket pieces (yet?), and it appears to be possible to create a conical shroud (see Ven's exploits at tankbutts and new shield fairings http://imgur.com/a/zLjez#8 ), a 5 m-to-3.75 m shroud-adapter compatible with the stock 3.75 m decoupler appears to be a nice solution, if design-intense one.