Allow non-default configurations

[robryals]

The plugin currently only works if you have a "default" configuration, and that is the only configuration you can use. Need to be able to specify a non-default. Gradle docs indicate you have to use the 'map notation'

dependencies {
runtime group: 'org.somegroup', name: 'somedependency', version: '1.0', configuration: 'someConfiguration'
}

[nsteffan]

robyryals, I fixed that problem in my fork and have a pull request to put the changes into here. Grab the plugin from my version and verify that it works properly.

[unsaved]

Nate's fix breaks test case "artifact". Check out Nate's fork or the nsteffan-manual here, run "gradlew test, and see at .../build/reports/tests/index.html that the artifact test is failing.

May well be that the problem is with the test case and not the new code, but new code isn't GA-ready until test case failures are addressed.