data-shell: more complex key targets

[pfuntner]

I would like a way to express more complicated key targets to json-shell:
- cd /foo
- cd foo/bar
- cd ../foo
- cd ~- or cd -?
- cd / - no this does not work - cd goes to the root but cd / gives an error.

        /> cd dict
        /dict> cd 1
        /dict/1> cd /
        '/' is not an integer: invalid literal for int() with base 10: '/'
        /dict/1> 

None of these can be done right now. You're limited to a single key without slashes. You can enter a slash but it's assumed that you're expressing a single key and the slash is part of the key.

These could also apply to cat and describe.