Revision 493294

Update dependency on plexus-container-default to 1.0-alpha-16-SNAPSHOT to fix child
container issues when maven builds use extensions;

Update dependency on plexus-classworlds to 1.0-alpha-7-SNAPSHOT to fix child container
plexus-bootstrap.xml loading problems.

Define p-c-d as a direct dep for maven-embedder; if not, an older version can be used
than is specified in the parent pom (dependencyManagement is not applied to transitive deps,
which is a bug (right?)).

Alter AbstractArtifactTask.java and MavenEmbedder.java to call the proper constructor
in DefaultPlexusContainer.