Merge pull request #98 in ASAPO/asapo from develop to master

* commit 'd7f36aaa':
  upadte changelog
  fix test
  producer retrieves stream info
  start providing last id via producer
  fix using non-positive ids
  refactor, add integration tests
  refactor, implement last_ack_id
  return nacks
  update hasicorp pack to latest versions
  implement ack function
  started working at acks
  refactor
  create position pointer if not exist on each get_next request
  update changelog
  refactor broker, added substream to callback, updated docs
  remove checking stream exists
  add quick start c++ examples
  change layout for c++ docs