Did a deep dive into [ipfs](http://ipfs.io/) last night. It has great
promise.

As a first step toward using it with git-annex, I built an experimental
[[ipfs_special_remote|special_remotes/ipfs]]. It has some nice abilities;
any ipfs address can be downloaded to a file in the repository:

	git annex addurl ipfs:QmYgXEfjsLbPvVKrrD4Hf6QvXYRPRjH5XFGajDqtxBnD4W --file somefile

And, any file in the git-annex repository can be published to the world
via ipfs, by simply using `git annex copy --to ipfs`. The ipfs address
for the file is then visible in `git annex whereis`.

Had to extend the external special remote protocol slightly for that, so
that ipfs addresses can be recorded as uris in git-annex, and will show up
in `git annex whereis`.
