leafpile3D -- minor mods

Added some modifications to the code by https://en.mathworks.com/matlabcentral/fileexchange/79727-leafpile3d, which is a super-fun script!

Stuff I changed compared to https://nl.mathworks.com/matlabcentral/fileexchange/79727-leafpile3d:
- closes all figures before starting the script
- Preallocated leaf info
- Made the leaves rotate around the z axis and in the x-y plane
- Made sure the leaves stay in the last position they were when they hit the ground
- Added some more dynamics, maple leafs have more resistance than the oak leaves
- Made the drag dependent on the size of the individual leaves