Use GPL compatible license

[nmaier]

It would be great if the license would be GPL compatible.

The 3-clause BSD license is not, due to the "advertise" clause.

[cpearce]

I'd be happy to change to a FreeBSD license, which is GPL compatible. Do you give permission for your code in PathEnumerator.* to have its license changed?

[cpearce]

And permission for your other contributions to be re-licensed to the FreeBSD license of course! ;)