CPAN Testers integration (via App::cpanminus::reporter)

This patch makes CPAN Testers reporting seamless to cpanm users
with App::cpanminus::reporter installed. It will conform to
the server API via the common client, handle any supported
transport mechanism and even setup a profile for new users.

Since all a user needs to start sending reports is install
App::cpanminus::reporter 0.10 or later, the patch also provides
a '--skip-report' option for cpanm to opt-out from sending any
reports.
Merge branch 'devel' of github.com:garu/cpanminus into devel