v0.5.0

• make parser library thread-safe
• fix bug which was preventing from event multilevel inheritance
• integrate Doxygen with a project
• add library API documentation (current documentation coverage: 17%)
• add license file for a project (MIT)
• add parser tests (current parser code coverage: 96%)
• fix buffer overflow in a ht_timeline_push_event()
• add task scheduler
• add CPU usage feature for Linux-based platforms
• many small bug fixes and minor improvements