Refactor xacml-pdp to remove various statics

Refactored xacml-pdp to eliminate a number of static fields.
Modified junit tests to allocate new ports for each test.
Also modified XacmlPolicyUtilsTest to convert path names to match
the file system so that the junit will work in OSs other than
linux.
Replaced logback.xml with a copy of the one from PAP to resolve
some issues.
Don't print entire message when discarding, as each PDP receives
messages for ALL PDPs.
Remove shutdown class from Main - just invoke this.shutdown()
directly.
Added additional comments to CommonRest.  Also modified port test
parameters.

Change-Id: Id8bf7216cdcb59a1a2cb4cb957fa44f640315cfe
Issue-ID: POLICY-1645
Signed-off-by: Jim Hahn <jrh3@att.com>