create heartbeat scheduler with named threads and as daemon

[valodzka]

This PR does 2 things:

1. Give heartbeat thread clear name so it's easy to spot it in thread dumps.
2. Set heartbeat thread daemon flag so it won't stop the app from exiting when the scheduler wasn't stopped correctly.

[darrachequesne]

@valodzka awesome, thanks!

[Clair-yoon]

@valodzka Hello, would it be possible to apply this change to version 1.0.2 as well?
I'm struggling with delayed heartbeats when the EventThread is busy.
Your help on this matter would be much appreciated.