Apache License 2.0
House cleaning.

Java    1.6   -> 1.7
Jaxen   1.1.1 -> 1.1.4
Guava   r09   -> 13.0.1
Jackson 1.8.1 -> 2.1.3
Junit   4.8.2 -> 4.11

se.pp.gustafson.marten -> org.github.chids.jaxen_json

System.err.println() replaced with SLF4J logging.
SLF4J Simple added as test dep.

Reformat source.