Using a different period for datalog file operations (datalog_write_ms)
and datalog alarm handling (datalog_timer_period_ns).
Writing datalog lines to local buffers in each timer tick and using
one new thread to write each local buffer to file.
Adding datalog_write_ms to the list of parameters from configuration files.
Using mutex for datalog alarm handling code.
Eliminating function pthread_getattr_np.