License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

ipfs1 docs read:

```
btc λ. ipfs pin
ipfs pin -

Commands:

        add         pin an ipfs object to local storage.
        rm          unpin an ipfs object from local storage.

        Use "pin help <command>" for more information about a command.
```

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

(The file path is omitted, but since only one object can be added at a time, I think this is ok)

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

not immediately useful, but nice to have

tagging you to make sure i didn't make a mistake here @jbenet

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

eg.

```
ipfs2 (cmd-ref-part2) λ. go build ./...; ./ipfs2 tour 0

Tour 0 - Hello Mars

Hello Mars

ipfs2 (cmd-ref-part2) λ. go build ./...; ./ipfs2 tour 10

ERROR
    no topic with id: 10

TOPICS

    0 - Hello Mars
    0.1 - Hello Mars 2

```

This commit adds the pretty-complicated decision function
to check whether a command should run on the daemon.

@maybebtc @mappum double check the logic?

I didn't know there were dragons here.

When casting errors we've gotta be careful. Apparently both values and
pointers satisfy the error interface. Type checking for one doesn't
catch the other.

cc @whyrusleeping @mappum @jbenet

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>