- Code refactoring
- Fixed the double firing of the place tree event
- Added leavesOverwriteLogs parameter to specify if logs should be replaced while generating leaves

Added support for multiple materials in the branches and leaves. To do this you should comma separate the materials.

Added a branch thickness parameter for larger trees

Changed the tab complete in the command so the materials are now lowercase.

- Fixed misleading IOException when creating the config file.
- Made the undo feature per player so people can't undo other peoples trees.