test,tools: capture boost::program_options in a try

When something fails boost::program_options throws an exception that
needs to be caught.

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
test: catch boost::program_options errors

And display it before returning on error.

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
tools: display boost::program_options errors

Instead of silently discarding them. Do not display the usage on error
as it will probably hide the error message that shows before it.

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
tools: move po::collect_unrecognized in the try block

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
tools: allow_unregistered() options

So that --debug-mon etc. can be parsed afterwards.

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
test,tools: indentation, whitespace only

Signed-off-by: Loic Dachary <loic-201408@dachary.org>