Fixes #450 : OOME on client authentication failure
Merge pull request #562 from pveentjer/fix/2.x/oome-client-authentication-failure

Fixes #450 : OOME on client authentication failure
Fixes #382 where a NPE causes the TimerTask from running again.
Merge pull request #563 from pveentjer/fix/2.x/382-heartbeattimer-hardening

Fixes #382 where a NPE causes the TimerTask from running again.
Fixes #478.
Added null check before creating instance proxies.
Fixes #566.
Small improvement.
Map.get() is not blocked by migration.
Made async executor thread count configurable.
Made compression configurable during migration.
Fixed issues when using WebFilter with client.