Tifig Versions Save

Complete conversion (with warning) even if EXIF data is missing.

• Updated libvips to 8.6.1
• Update heif library to latest commits

• Output path is now optional which allows piping (Thanks to @Kostanos for suggesting this)

• Persist Exif metada when converting to JPEG
• Better error message for unsupported HEIFs

• Fix endless loop when opening anything other than a HEIF file.

• Add thumbnailing functionality to tifig
• Show tifig version

• Support for different output image formats
• Modern ffmpeg invocation
• Simplified build system
• Added option for static builds
• Testsuite
• Docker support

• Libav integration
• Threads/async

First release with basic functionality: * Convert full size HEIF images to JPEG

• Thumbnail exporter
• Keep orientation in JPEGs