RADAR-370: send property to identify explicit vs implicit offlines
Explicit/implicit sent to redis

Also updates to tests in order to avoid zombie process
Use radar_client v0.7.3
Merge pull request #83 from zendesk/samshull/RADAR-370-implicit-explicit-offlines

RADAR-370: send property to identify explicit vs implicit offlines
0.7.4
Merge branch 'master' into vanchi/better_presence

Conflicts:
	core/lib/resources/presence/index.js
	core/lib/resources/presence/local_manager.js
	core/lib/resources/presence/remote_manager.js
	tests/client.presence.test.js