v1.0.6.8 - Crash fixed; More Optimization

On the surface, this is a small update, but it could be pretty significant for some players!

• Fixed a memory leak which could cause crashes for some users after extended play sessions.
  
• Optimizations to reduce reliance on shaders. This can provide a fairly significant performance boost on devices which have integrated graphics or a weaker GPU.
  
• Fixed an issue with grass spawning inconsistently. (That is to say, it often didn't spawn!)