comm-files: improve usage wording

Signed-off-by: Christopher Larson <kergoth@gmail.com>
gist-cmd: add little wrapper script

Sends both the command being run and its output to a gist.

E.g.

    $ gist-cmd echo hello, world

Puts this in a gist:

    $ echo hello, world
    hello, world

Signed-off-by: Christopher Larson <kergoth@gmail.com>