2.4.0

Important Change:

• requires Ruby 2.1 or later
• released along with Autobuild 1.12.2 Changelog

Bugfixes:

• fix backtraces leaking to the user
• fix errors in the Yum and Zypper osdep managers (thanks @vbargsten, #158)

New functionality:

• git_server_configuration can now lazily resolve the configuration, which allows to
  essentially remove the gitorious.org definition in a backward-compatible way.
• cli: allow autoproj cache to cache a single package and its dependencies
• cli: added autoproj exec
• cli: added autoproj which
• cli: added OS dependency query to autoproj query