Complete rewrite in Rust, additional features

Features:

• Rewritten from scratch, in Rust
• No external program used anymore
• Now ignores border
• Shrinks only larger areas (avoid cutting gaps between text lines)
• Directory scan mode: finds newest file in a specified directory

Bugfix release

Bug fixed: the program skipped rightmost and bottom areas if they were empty.

Beta

Known issues, no distribution solution, but works. See README.md.