Tests/doc/examples: Auto-detect version of dependency to add to war.

In various container tests (jetty and tomcat ATM), there's hard-coded version of weld-servlet being packed to WAR.
I changed this to take some class's package's SpecificationVersion so that it's aligned with pom.xml (or whatever version is on classpath).

https://gist.github.com/908830

I suggest to make this a standard for tests.

Further, I wonder whether MavenDependencyResolver can resolve rather by a class than a string.
If a class comes from a properly created Maven artifact, then it is possible to reach for this jar,
look at it's META-INF/..., take the G:A:V and resolve using that.
But that's rather for Karel Piwko's attention.

Also, I thought of having weld-servlet packed automatically by some test enricher, so that user wouldn't have to do this at all.
If it's size (2.1 MB) is a concern, it could scan for CDI annotations and if found, it would pack it.
Doable?