Adds summary: to separate summaries in single file.

Thus we have:

summary:
command: some-command
...
...
...

summary:
command: some-other-command
...
...
...

Before it was done with comments (#), but that was not very explicit.
Perform final stat if size on close is unknwon.
Disable makeflow monitor time-series,opened-files.

They can be enabled now with:
--monitor-with-time-series
--monitor-with-opened-files