Allow specifying classifier for default package in deployment settings

[Krever]

Hi there

This PR introduce the ability to provide an artifact classifier for default packages when calling makeDeploymentSettings.

We need this feature in our build process and I see no other workaround that to produce second artifacts with addPackage call.

[muuki88]

Thanks 😃
LGTM . No idea why this wasn't there in the first place.

[muuki88]

I restarted the travis build as it seemed to have timed out.