Added fading between gamestates with a new system that allows shutdown time for systems when switching gamestate.
Fixed a rare crash.
Merge pull request #161 from Revolutionary-Games/122-xgamestate-fading-music

Fading music between gamestates with new system feature.
Merge branch 'master' of https://github.com/Revolutionary-Games/Thrive
Added photosynthesis, a chloroplast organelle, and environmental CO2 emitters.

Notes:
- Chloroplast organelle is placed in editor with hotkey [P]
- Water and sun are everywhere, so photosynthesis only requires CO2
- New OrganelleFactory streamlines microbe creation and modification
- definitions are now on the git repo
Merge pull request #172 from Revolutionary-Games/146-photosynthesis

Photosynthesis added. This also involves a refactor to how organelles are created, they now use factory for normalized creation.
Merge branch 'master' of https://github.com/Revolutionary-Games/Thrive into 165-rolling-grid

Conflicts:
	scripts/microbe_editor/microbe_editor.lua