Effects on the root part disappear when reverting to launch.

[eggrobin]

Steps to reproduce:

• HotRockets! on clean install.
• Build a vessel whose root part is a BACC SRB, with a Mk1 pod on top.
• Launch. Smoke appears and behaves as expected.
• Press ESC, revert to launch.
• Launch. The nozzle glows, but no smoke is emitted. A similar issue occurs when loading a vessel whose root part has a ModelMultiParticlePersistFX from a save: no smoke.

Partially unrelated: I found this out while trying to implement buoyancy, better collision and other things for your particles, and this is looking promising (the exhaust velocity on this screenshot is too low, and some things still need to be tweaked, but smoke doesn't just reflect or glide, it floats): You don't have a dev branch though, so I'm not sure where my pull request should go when I get this to work.

[sarbian]

There is a dev branch now. Feel free to contribute :+1: