PT-47192933:  A race condition in updateSubscription allows addSubscriptionSet to add multiple dialog event subscription to the same URI.   This will eventually overload the system overtime because the duplicates will never be destroyed.
PT-47609155 CON-433 - Sort list of locations such as the primary is always first. Then, list is sorted by location_id.
code review: Alex M
PT-47192933:  Modified checking of subscriptionset existense check only for timed insertions.
Adding threadpool classes

Adding support for POCO as dependency for threadpool implementation

Use thread pool for register processing

Added macros for POCO

Updated test

Removed support for blocking schedules