Prepare release 2.4.0

Prepare release 2.3.1.

Prepare release 2.3.0.

Update readme and usage instruction.

Merge pull request winnfsd#26 from marcharding/fix-log-timestamp

Fix odd timestamp.

Fix appveyor link (organizations seem not to work).

Retroactively tag version 2.0.0 to omit avoid versioning gap.

Add tree.hh

Merge branch 'master' of https://bitbucket.org/yannschepens/winnfsd-new