[Patch 0.20] Complete Redo of 'Tree Fall Down'

Hi!

As I've mentioned before there had been some problems with the 'Tree Fall Down' project.  After using said project for a game I was prototyping I stumbled upon some weird issues and inelegant design choices. I have now totally redone the 'Tree Fall Down' project and although it may not be perfect yet and I'm still labeling it as a prototype, it has definitely improved a lot.

I have also added a new feature to the project. Now the falling object will crush (or be crushed) any objects it falls on, determined by their 'hardness' variables.

Secondly I have removed the 'tree sprites' from the project. It only makes things more complex and I decided I want to present this project more broadly usable as I did before, as it most definitely can. However, these sprites are still available in the 0.10 version of this project. Feel free to use them, and although crediting is not required please do not claim my pixel art as your own.

I hope most issues with this project now have been resolved. If you do find any oddities or bugs please let me know, either in the comments or on my discord channel (Link in profile).

Thanks!

RanDB