Change the AutoValue pom.xml so that it uses the Maven shade plugin to i...

Change the AutoValue pom.xml so that it uses the Maven shade plugin to include all dependencies in the generated jar, and to rename most of them. This is intended to address https://github.com/google/auto/issues/156.
Yes. I think it might be worth investigating whether we can make this work. However, the situation after this PR is strictly better than the situation before because at least we have managed to shade asm and Guava. Asm in particular did actually show itself to be a problem.