Add support for excluding subdirectories

[atc0005]

Scenario:

1. Recursively process items in /var/log/ older than 30 days
2. Exclude /var/log/mail/ directory since those are rotating properly (as all log files should be) and they're kept 60 days (just an example number)

I should be able to use an options such as --exclude /var/log/mail --path /var/log/ --recurse to get this effect.

[atc0005]

Note: This is likely a duplicate, but filing it quickly just in case it isn't.

[atc0005]

This would have been a lot easier to work in after refactoring configuration handling to match recent projects, but I'm optimistic that I can work it in within the current design.