Add ISC License

Overdue...

Update README to reflect that it works!

The old README had a lot of "when implemented" and "will..." language.
This patch updates it to reflect what is actually done (and the fact
that the MVP is totally workable!)

Add initial MVP

As shown in the README, this is already quite a flexible tool (by
reading stdin, the content to practice can be easily filtered to
what you'd really like to practice).

The inspiration for this project came to me after a couple days of
battling with the punctuation keys on my new Atreus keyboard.

I started at one point line-by-line copying one file by hand, but
the constant back-and-forth looking between buffers made it slow.

This is a significant improvement... in under 50 lines of Perl :)

initial commit