Revision 163323

o Added dependencyDefaults section to POM.

  The nested <dependencyDefault> element closely mirrors the <dependency> element specification.
  It provides the ability to set url, artifact, properties, version for a dependency that matches on
  {groupId, artifactId, type}. Url, artifact, and version will only override the dependency's values if
  the dependency doesn't provide the value, and (in the case of url and artifact) the dependency
  doesn't provide a version (url and artifact are assumed to be version-specific).

  Properties will only be overwritten, and only in the case where the dependency
  doesn't specify them.

  Dependencies are validated after merging with defaults, since version is not required
  on either <dependency> or <dependencyDefault> but is required between the two.

o Added component interface/default impl for injecting project defaults.
o Added unit and integration tests.