RubyMaven: follow new API

See also 34f22dd2cf0200ccd7080cc2f16cc0be24323665.

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
.gitignore: ignore tests output files

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
Aether: add support for classifiers

Respect classifiers in Aether#getResolvedCoordinates.

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>