Mission Editor feature request - detect and report static assets that are not parented to an unit for missions with ships

[pablofe]

When building missions with ships, it is fairly easy to forget to attach a static asset to an unit (like when placing crew and equipment on a carrier), which results on the asset not showing up.

Static assets over water, other than ships, don't make a lot of sense, so it would be helpful for the Mission Editor to check and flag this for the user.

The Mission Editor should bring this to the attention of the user (and perhaps have this an option to toggle this on/off), perhaps by doing a sanity check before saving.

[upyr1]

There should be a check with it snapping to a ship like a landing waypoint