Docs: correct license and fix typos

[MarceloRobert]

Changes

• Corrects license in the README file
• Fixes a couple of typos, missing words, and extra words in the other docs

[knurd]

Thx for this, much appreciated. Looks fine, but when I wanted to apply this it got me thinking that we should have a CONTRIBUTING.md file which mandates a DCO. I just added one.

Could you please sign-off your changes to be in line with that new rule? Sorry for the trouble, but it's for the better.

While updating the commit, feel free to remove the "If you think a more liberal license should be used, let regzbot's author know what you'd prefer, as for now it's still quite easy to change the license." in the commit that updates the license in the readme, as that is now obsolete.

[MarceloRobert]

Could you please sign-off your changes to be in line with that new rule? Sorry for the trouble, but it's for the better.

Sure, I'll change it as soon as I can because I still have to setup the repositories on my personal machine; next week at most, if not tomorrow.