Expanded the activity aggregation reset tests

Added some test code that will assert that an activity stream that holds
previously aggregated activities can be reset correctly
Compressing tests log when uploading to S3
Merge pull request #857 from simong/travis-master-logs-gzip

TravisCI: zip logs before shipping them to S3
(Issue 732) Route group join notificiations to group managers
(Issue 732) Add an email for group join notifications
(Issue 732) Review followup
(Release 6.0.0) Bump version
(Release 6.0.0) Remove shrinkwrap
Resetting aggregation asynchronously when marking notifications as read

Aggregation for a notification stream is reset asynchronous from the API request.
An event `resetAggregation` has been added that indicates when a stream gets
its aggregation reset.
(Issue 732) Remove accidental timeout
Merge pull request #732 from mrvisser/issue-732

Group join notification
Merge branch 'master' into activity-aggregation-reset

* master:
  (Issue 732) Remove accidental timeout
  (Release 6.0.0) Remove shrinkwrap
  (Release 6.0.0) Bump version
  (Issue 732) Review followup
  (Issue 732) Add an email for group join notifications
  (Issue 732) Route group join notificiations to group managers
  Compressing tests log when uploading to S3
Email stuffs