Arrowhead Framework 4.0

Here are the biggest changes and new features in this release, since version G3.2 M3:

• Event Handler Core System implementation with a matching Subscriber and Publisher client implementation as well

• C++ Provider and Consumer client implementation

• TimeToLive feature: Service offerings now can be registered with a "timeout" into the Service Registry.
  If the timeout is up, the Provider no longer guarantees the Service offering, and the Service Registry
  can delete the entry from the database.

• New Orchestration Store interface with 4 different query methods

• Property files are reworked to be more simple, with better default values, and to provide more configuring options

• Core Systems now give a list of missing fields, when a REST request is missing mandatory information

• Improved the database connection with a connection pool manager

• JSON serializer library replaced with a new, more powerful and configurable one

• Orchestrator now filters results based on Service interfaces