Add a v0.0 tag so that git-describe works

[mithro]

Would you mind adding a v0.0 tag to commit 1f82264 ? That will mean that git-describe command produces useful output.

$ git tag -a v0.0 1f8226443247a1122a7a286ef6989c1e12039a0b -m "First commit."
$ git push origin v0.0

Then you get the following on git describe

v0.0-21-g3a02468

[mithro]

@antonblanchard - Could you look at this?