Clean up dependencies, enable CI and proper releases.

[anjackson]

The goal is to reduce linkage to IA Maven artefacts, so that we can build using a SonaType POM and make clean releases. Should also enable Travis CI builds to work, and ensure that proper releases will go to Maven Central.

[anjackson]

See pull request iipc/webarchive-commons#1 for the first stage of this.

[egh]

Can we close this issue? I believe Andy has done all this work. Thanks, Andy!

[anjackson]

Yes, this is ok now, I think. Thanks.