Make thread pool utilization calculation more accurate.
Bugfixes for the JSON-RPC sub-system.
Fix ITL definition for the replication component.
Add cluster.conf to the Makefile.
Fix deadlock in ReplicationComponent::EndpointConnectedHandler.
Bugfixes for the socket subsystem.
Fix memory leaks in the config parser.
Refactor the socket subsystem.
Bugfixes for the replication component.
Optimize replication messages.
Fix case where all threadpool threads are killed.
Fix FIFO bug.
Remove unused #include.
Fix crash when application config item is missing.
Don't link items after we've encountered a compiler error.

Fixes #3930
Implement host check commands

Fixes #3674
Implemented Icinga 1.x time period parser.