BOUNDS returns wrong values when Waterfall mod is installed.

[Dunbaratu]

I was noticing my landing script thought my vessel was over 18 meters tall, when clearly it was only about 3 or 4 meters high.

Diagnosing this, it turns out that engines return wrong bounds when the Waterfall mod is installed. It seems to be that the exhaust plume is being counted as part of the engine's dimensions (even when the throttle is zero so the engine isn't firing).

To reproduce:

1. Have these two mods installed: Waterfall, and Stock Waterfall Configs.
2. Make a ship that uses a Terrier engine (may happen with other engines too, but this is the one I noticed it with).
3. for p in ship:parts { print "bounds for " + p + " is " + p:bounds. }
4. Note the :RELMIN for the Terrier engine part has a negative Z of about 18.1 meters.

To fix this we should probably have some better logic within bounds calculations to know which components are "not physical" and therefore should not count. Something that's purely visual with no colliders probably shouldn't count.

[Dunbaratu]

Probable cause: PartValue.GetBoundsValue() iterates over all Meshes in the component with this:

MeshFilter[] meshes = Part.GetComponentsInChildren<MeshFilter>();

Some of those meshes will be visual-only (and will be unnecessarily detailed with more vertices than the object "physically" has in its collider).
It should probably be iterating over just the colliders, not all the meshes, using this:

Collider[] colliders = Part.GetComponentsInChildren<Collider>();

The Collider type has a .bounds member just like the mesh type does so presumably the algorithm from there down shouldn't need to change that much.

[Dunbaratu]

Closing to redirect it over to issue #2942.