-disposition:
Clarify the meaning of the default value, and how the '+' and '-'
prefixes work. Add more examples.
-stats:
Clarify that it appears as an "info"-level log.
-progress:
Add info about the "progress" key's value being "continue" or "end".
Add an example of logging to stdout.
Signed-off-by: Soma Lucz <luczsoma@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>