Added check for pom 'packaging' in maven publication tests
Better DSL docs
Don't use ivy when publishing to maven with the maven-publish plugin
- Inlined lots of stuff
Removed a the last vestiges if ivy from maven publication
- Don't use ArtifactPom class as it contains magic handling of jar/war/ear and nothing else
- MavenPublication determines the packaging from the type of the main artifact
Added very basic end-to-end support for adding additional artifacts to a maven publication
- Added MavenArtifact interface as public representation of a maven artifact
- MavenPublisher deals in terms of MavenArtifacts, not PublishArtifacts
- Can add an AbstractArchiveTask as an additional artifact to MavenPublication
- Still pending:
  - Solid, tested implementation of MavenArtifactSet
  - NotationParser for constructing/adapting input to MavenArtifact
  - Ability to adapt existing live collections (eg PublishArtifactSet, FileCollection)
  - Lots of integration test coverage