Add proper logging framework

Added SLF4J backed by Log4j2. This includes adding dependencies for the
LMAX disruptor, the JCL over slf4j bridge, and the restlet slf4j
extension. It also requires deletion of the existing log properties
files for jetty and log4j, and Maven exclusions for other logging impls.
Bump blueprints to 2.5.0-SNAPSHOT (using sonatype nexus repo) and force
use of Neo4j 1.9.5.
POM flesh out (for org, licenses, devs, etc.) and removal of
unnecessary scope tags.