Refactored archive logic Almost all (un)archive code now lives in bash libraries. To add support for a new compression or encryption algorithm, updates only need to be made in `archive.bash`, `unarchive.bash`, and the parser in `mktar-batch`. `mktar-batch` has eclipsed `mktar` when it comes to explicit command line options. Much of the logic wqas removed. `mktar` now soleyl exists as a clever utility that guesses encryption/compression preferences based on the output filename. Filename is now mandatory. Refactored tests to reflect these changes. Standardized use of here-strings in a couple of places.
Full support of age encryption mktar-batch now supports non-interactive age calls, though I've added a dependency on expect. tarcat, tarls, and untar now know what to do with .age files. They also now know what to do with Zstandard compressed files that use .zstd (instead of .zst).
Refactored code into multiple 'packages'. One day these may be independently installable. For now it's just an organization method. Rewrote main README and added per-package READMEs. Also: bug fix on whiched and whichvi. They formerly propogated an error if $EDITOR or $VISUAL were set to a non-existant executable. Also improved the inline documentation.
Specify full path to POSIX utilities; Clean up scripts' output
Initial commit of cleaned-up dev branch