Auto merge of #3560 - KalitaAlexey:make-doc-subcommand-print-duration, r=alexcrichton
authorbors <bors@rust-lang.org>
Wed, 18 Jan 2017 23:01:03 +0000 (23:01 +0000)
committerbors <bors@rust-lang.org>
Wed, 18 Jan 2017 23:01:03 +0000 (23:01 +0000)
Made doc subcommand print duration

This PR makes `cargo doc` print duration.
Fixes #3016.


Trivial merge