1) Added active time calculation (this is duration excluding context switch time).
2) Columns "Duration", "Self Dur.", "Self %", "% / Frame", "Active time", "Active %" in Plain mode shows total values per frame (sum of all values per frame).
Known issue: if context switch events occur out of profiled blocks then percent/thread may be calculated wrong as it is calculating relative to thread profiled time (which may be a very low value).
* (Core) Context switch events also register threads for current process;
* (Core) Writing process id into output file (old files still could be opened);
