Add --dry-run option to publish sub-command

Add --dry-run option to publish sub-command

Squashed commit of the following:

commit deed1d7b99c1cd142f7782d3b3b782d949e1f71f
Author: Wesley Moore <wes@wezm.net>
Date:   Fri Jul 15 13:35:01 2016 +1000

    Remove --dry-run and --no-verify mutual exclusion

commit 8a91fcf2a1aa3ba682fee67bb5b3e7c2c2cce8ef
Merge: 0c0d057 970535d
Author: Wesley Moore <wes@wezm.net>
Date:   Fri Jul 15 13:30:38 2016 +1000

    Merge remote-tracking branch 'upstream/master' into publish_dry_run

commit 0c0d0572533599b3c0e42797a6014edf480f1dc2
Author: Wesley Moore <wes@wezm.net>
Date:   Tue Jul 12 08:03:15 2016 +1000

    Improve grammar in --dry-run option

commit a17c1bf6f41f016cafdcb8cfc58ccbe34d54fbb8
Author: Wesley Moore <wes@wezm.net>
Date:   Mon Jul 11 14:17:41 2016 +1000

    Add test for passing no-verify and dry-run to publish

commit 284810cca5df3268596f18700c0247de2f621c98
Author: Wesley Moore <wes@wezm.net>
Date:   Mon Jul 11 14:51:38 2016 +1000

    Add test for publish --dry-run

commit 8514e47fbce61c20b227815887a377c25d17d004
Merge: 2b061c5 ef07b81
Author: Wesley Moore <wes@wezm.net>
Date:   Mon Jul 11 08:27:10 2016 +1000

    Merge branch 'publish_dry_run' of github.com:JustAPerson/cargo into publish_dry_run

commit ef07b81617df855328c34365b28049cd9742946c
Author: Jason Priest <jpriest128@gmail.com>
Date:   Tue Jun 9 23:11:51 2015 -0500

    Improve publish `--dry-run`

    Catch a few more errors by aborting midway through transmit().

commit 0686fb0bf92a09bcbd41e15e23ff03a0763c5d08
Author: Jason Priest <jpriest128@gmail.com>
Date:   Tue Jun 9 14:38:58 2015 -0500

    Teach publish the `--dry-run` flag

    Closes #1332