fix(message-properties): add missing field and correct null values
fix(message-properties): add missing field and correct null values

Message.Properties omitted the "correlation-id" field, and did not
properly handle undefined values for the following fields:
  - absolute-expiry-time
  - creation-time
  - group-sequence

noodlefrenzy/node-amqp10,danlangford/node-amqp10,mbroadst/node-amqp10,robblovell/node-amqp10