* Make the license less restrictive. See #14
So that people can use _just_ main.sh without bothering with also
distributing the license
* Add license update to changelog
* Add a comment about expansion, see #26
* Use an unmodified MIT License, with the more permissive clause inside the code
As modifying the MIT License will needlessly (but rightfully) cause
suspicion
* Credit @bravo-kernel for his feedback
* Fix another typo
* Reword copyright
