salt-minion: Add a Salt State minion image

If you already have a Salt setup, it might be easier to use Salt to
provision your container than to convert your Salt configs into
Dockerfiles.
*/README.md: Replace '-name' with '--name' and '-link' with '--link'

Docker has adopted GNU-style long options with v0.8.0 :) [1]:

  First step toward getopt style flags:

  As we keep compatibility with flags like -dns we can't have -i -t ->
  -it but at least - and -- are now correct.

[1]: https://github.com/dotcloud/docker/pull/3322
     e71dbf4 (update commands.go, 2013-12-23)