making JCR optional

[tom.baeyens]

By reworking the JCR support, i introduced some subtile dependencies. E.g. including the mapping for the JcrNodeInstance, created a dependency on the jcr jar.

I'm removing those kind of dependencies now.

Next step should be to document all the steps required to include JCR.

Is that OK with everyone... that we see JCR as an optional package that is not included by default ?

[kukeltje]

as long as integrating extensions (this one or any other) will be as easy as breathing