Close RegionFiles.

RegionFiles weren't being closed after being read from, which could cause
an error for having too many files open.

This commit fixes the issue by closing RegionFiles after they're no longer
needed.
Improve user feedback.
Only consider .mca files when scanning.
Update to version 1.1.
Fix the horrible formatting.
Update versioning to be simpler.
Add "force" option to save-structures command.

This option forces a drop of the existing structure data, causing a
clean structures file to be stored to disk.
Add tab complete for save-structures command.
Check if we're able to generate structures before running.
Don't print command help when invalid worlds are provided.
Update to version 1.2
Add README.md.