Update handling of recurse parameter to match Pinto > 0.093.

With 0.093, the command line parameter used to specify whether 'pinto
add' should recurse was changed to either '--recurse' or --no-recurse.

This commit updates the plugin and adds a set of tests that hijack
Dist::Zilla::Plugin::Pinto::Add::_run_pinto and confirm that it is
being specified correctly.
Merge pull request #13 from hartzell/master

Update handling of recurse parameter to match Pinto > 0.093.