Specifying the notes dir with an absolute path causes InvalidRelDir error about neuron HOT 1 CLOSED

Support for absolute paths (temporarily) got removed in srid/rib#134

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I'd like to add back support for absolute paths, but only after carefully thinking about the location of the Shake database directory - which at the moment is always in the current working directory. So if you are currently under ~/somedir and do neuron ./foo/bar ..., then the Shake database directory will be stored under ~/somedir/.shake. But if you are elsewhere, and run neuron with ~/somedir/foo/bar - that database won't be used.

This behavior is normal for static sites written in rib (as current working directory is always the git repo), but for a tool that extends it (like neuron) I think we should have to be explicit in saying where the Shake database has to be stored. I'm inclined to store it the notes directory itself; assuming that won't be problematic, support for absolute paths can be restored (internally neuron would convert that relative path before passing it to rib).

from neuron.