Auto merge of #2918 - munyari:man-pages, r=alexcrichton
authorbors <bors@rust-lang.org>
Tue, 26 Jul 2016 23:12:19 +0000 (16:12 -0700)
committerGitHub <noreply@github.com>
Tue, 26 Jul 2016 23:12:19 +0000 (16:12 -0700)
Add man pages for cargo subcommands

From #2789

- [x] fetch
- [x] login
- [x] metadata
- [x] pkgid
- [x] rustc
- [x] rustdoc
- [x] uninstall
- [x] version
- [x] yank
- [x] generate_lockfile


Trivial merge