Construction controls update

Over the last couple of weeks, I’ve made a couple of changes to the controls:-

• After parts have been attached together, you can now cycle their attachments between available types (e.g. rigid or hinge), by hovering over attachments and pressing E.
• Cloning and deleting entire constructions is now done via a separate menu (accessed by holding Shift + Q).

More rendering improvements and other fixes

Also now in the build:-

• A load more rendering improvements following on from the previous overhaul.  The main difference being that the sky and distant water are now rendered before everything else, using another separate camera with a much larger far clip distance.  This prevents the horizon line from being clipped out.
• Time-of-Day upgrade.
• Reference grid in inventory part preview images.
• Force zones now slow down objects at world boundaries.
• A bunch of bug fixes.