v0.3.0

Breaking changes:

• Use filetailor.yaml file instead of yaml/*.yaml directory. To upgrade, combine all .yaml files in the yaml directory into a single filetailor.yaml.
• Rename command options: no-bak to no-backup and yes to assumeyes.

Improvements:

• Add difftool support for subfiles
• Modernized packaging tools and dependencies

Bug fixes:

• Prevent crash if diff program not listed
• Check for subfiles correctly
• Create .config directory if not present
• Fix issues with indenting for multi-line blocks