More realistic water/sky, day/night cycle

After some considerations I decided to go on with more realistic graphics for this prototype (I was considering previously some "watercolor" or "painting" look, inspired by many marine paintings). I want to keep the synergies between this prototype and my long-term project ("The Weather Gage"). That project is still using the older Unity pipeline (Built-in) and an old weather & day/night system, but I intend to update mid-term to the newer high definition pipeline. This update is a test for the sky and water of that graphic pipeline and also implemented a simple day/night cycle. The reduced visibility during the night should add some challenge to the navigation (more difficult to spot the floating ice and coast profile). The cycle is accelerated (no real 24-hour cycle) so the player can experience some quicker contrast
The rest of the graphics are kept still pretty simple (prototype) and will have to wait.