Switch license to MIT and add some text to README
Don't allow "[v=]*" prefix before matches any more

`SemVer.clean` can take care of most cases where this would be used and
let the using source take care of stripping them otherwise.
Copypaste derp
Merge commit 'f98700688a31443aa70e36042977ba8f439ed833'

Updating to FichteFoll's most recent commit