Removed 'Editor' and 'Standard Assets' from 'Assets' folder.
Unity default assets shouldn't be added as a whole.
Any asset needed should be copied/pasted to the appropriate sub folder
in 'Resources'.
Added Assets packages for lava and water3 (from Unity standard assets).
Added Assets used for smoke particle effects in Level 3 (from Unity
Standard assets).
Moved some lava assets to lava package folder.
Added ImageEffects assets package from Unity standard assets.
Added Water assets package from Unity standard assets.
Added "Standard Assets" folder is now ignored by git.
If sthg is needed from it, just copy the elements you need to the
"Packages" or "Resources" folder.