auto merge of #509 : alexcrichton/cargo/features, r=wycats
authorbors <bors@rust-lang.org>
Tue, 23 Sep 2014 01:53:52 +0000 (01:53 +0000)
committerbors <bors@rust-lang.org>
Tue, 23 Sep 2014 01:53:52 +0000 (01:53 +0000)
This feature was outlined in #385 [1], and documentation has been included as
part of this commit.

[1]: https://github.com/rust-lang/cargo/issues/385#issuecomment-53917539

Closes #385


Trivial merge