Add support for short options.
-S --sources List sources
-s --source View articles for source
-a --article Select article number
-o --output Output: default, json, url
-O --open Open article in browser
motivated by dshaw, switched to using optimist.usage(). you can now output the article listing as JSON too.
upped version #.
Merge pull request #4 from bcoe/patch-open

Pulled in dshaw's Command LIne Improvements