plugin parameters and anything else.

 We once had a document that Vincent and I agreed upon and I was about to
 implement it and then I disappeared for 8 months so it never came to pass.

 So I guess it's important to figure out what people are using properties
 files for and see if we can't incorporate it all into the POM. Or if we do

import org.apache.maven.api.services.ModelRepositoryHolder;
import org.apache.maven.api.services.RepositoryFactory;

public class DefaultModelRepositoryHolder implements ModelRepositoryHolder {

    /**
     * The possible merge modes for combining remote repositories.
     */
    public enum RepositoryMerging {

        /**
         * The repositories declared in the POM have precedence over the repositories specified in the request.
         */