some nodes were located in org.jbpm.graph.def and some were located in org.jbpm.jpdl.def. this was confusing.

we reorganized the package structure like this:

org.jbpm.graph.def contains all structural elements of a process graph, including the Action and Node base classes.
org.jbpm.graph.node contains all node implementations
org.jbpm.graph.action contains all action implementations
org.jbpm.jpdl contains all code related to xml parsing and process archive packaging