Auto merge of #4595 - treiff:update-appveyor-badge-documentation, r=alexcrichton
authorbors <bors@rust-lang.org>
Sun, 8 Oct 2017 02:32:33 +0000 (02:32 +0000)
committerbors <bors@rust-lang.org>
Sun, 8 Oct 2017 02:32:33 +0000 (02:32 +0000)
Update docs for appveyor badge.

Can now optionally specify the appveyor `project_name`.

Related PR: [rust-lang/crates.io#1111](https://github.com/rust-lang/crates.io/pull/1111)
Related Issue: [rust-lang/crates.io#587](https://github.com/rust-lang/crates.io/issues/587)


Trivial merge