Dynamic day/night cycle

[AndrewDunne]

Implementing changing time of day, will be modifying the 'island' level

• [x] Time system
• [x] Changing HDR
• [x] Changing directional light
• [x] Changing ambient light
• [x] Memory swapping
• [x] Napping feature
• [x] Changing heightfog
• [x] Changing heightfog (water)
• [x] Changing atmospheric fog
• [x] Changing water caustics
• [x] Changing caustics
• [x] Appearance polishing
• [x] Day state transition

[AndrewDunne]

Update: Instead of doing a continuous time of day where you can see the sun move across the sky and the sky change color, it'll be a transition between three states of day, sunset, and night. Getting the continuous transition to look good is difficult and not worth the effort.