Bukkit

Fixes:
- Fixed treesniper adapting latest FAWE logic
- Fixed a lot of exceptions when commands were used not following their proper syntax
- Fixed improper material examples in command syntax
- Fixed entity brush not taking protected areas into consideration

Changes:
- The sign overwrite brush now stores files in its dedicated folder `signs` inside the FastAsyncVoxelSniper folder.
- A few command colors have been changed that were hard to read.

Additions:
- Added a tab-completion method to Brush interface, allowing each brush to complete it own parameters.
- Added a tab-completion handler to brushes that accept parameters, such as biomes, block types or precise arguments.
- Improve brush info, propagating a sane command format. You can append the `info` parameter behind any brush to view the arguments and command syntax it uses, e.g. `/b sb info`
- Use real subcommands instead of parsed parameters such as `y15` -> `y 15` to match consistency with other subcommands.