Doc: add and fix docs for summary report subject line

[ShawnPConroy]

I added the subject line to the cli help response, and updated the code doc to use = for the parameter, and fixed where the quoting was.

The example uses unescaped spaces, which works fine for me. But the code says spaces must be escaped. I didn't fix this inconsistency, as you may want to go in a direction where one or the other is required. But as it seems to work with spaces, I'd recommend leaving it as allowing unescaped spaces.

Thanks for implimenting the subject line feature.