freehep is no longer in snapshot status and now has a 2.0 release. Pom has been updated to reflect this.

Change-Id: I997aceece5f038cf92bd24744692436f5873f2cf
Removed existing JAXB based XML serialization.

Change-Id: Ie893e09569e45be8592c0a8a607753c02df0575b
Added back the JAXB unit tests removed in the last commit in XStream form.

Change-Id: Icb46a15f510b6f602ffb74e30adf30b8d36a7cd2
Merge branch 'xstream' into endpoints

Conflicts:
	src/main/java/com/syncleus/dann/graph/AbstractAdjacencyGraph.java
	src/main/java/com/syncleus/dann/graph/AbstractBidirectedEdge.java
	src/main/java/com/syncleus/dann/graph/AbstractTraversableCloud.java
	src/main/java/com/syncleus/dann/graph/Graph.java
	src/main/java/com/syncleus/dann/graph/ImmutableAdjacencyGraph.java
	src/main/java/com/syncleus/dann/graph/TraversableCloud.java
	src/main/java/com/syncleus/dann/graphicalmodel/AbstractGraphicalModelAdjacencyGraph.java

Change-Id: Ibeaa17c591a46dbce29e3b29f8803e1461398a11