Strip null values or properties

When the STRIP_NULLS URI flag is included on a representation factory,
configure jackson to strip nulls from its embedded objects, and manually
ignore null properties.
Updated version number, and jackson dep
[maven-release-plugin] prepare release halbuilder-json-3.1.1
[maven-release-plugin] prepare for next development iteration
Merge branch 'release/3.0.2'

* release/3.0.2:
  [maven-release-plugin] prepare for next development iteration
  [maven-release-plugin] prepare release halbuilder-json-3.1.1
  Updated version number, and jackson dep
  Strip null values or properties
Merge tag '3.0.2' into develop

Rel

* tag '3.0.2':
  [maven-release-plugin] prepare for next development iteration
  [maven-release-plugin] prepare release halbuilder-json-3.1.1
  Updated version number, and jackson dep