Fixed several cosmetic code issues. Improved detection of same/different disk detection. Switched shared_ptrs to use std implementation instead of boost one. Cleaned up includes in headers. (CH-259)
Performed de-duplication of the progress data and stats data (i.e. current file processed size was available in both progress data and stats data and not always updated simultaneously). There is no separate progress data anymore - everything is now placed in the stats data. (CH-124)
Switched row data handling to not use shared pointers nor RowData object to pass information (optimization to slim down the serialization cost) (CH-103).
Rewritten statistics handling for sub tasks, tasks and task manager (this commit introduces some issues that needs to be further fixed). Only basic tests performed (!)