Adding comment indicating newer satisfying version

currently, bower list reports the most recent version
this change adds to that the most recent version that satisfies the rule in bower.json

eg :

├── requirejs#2.1.3 (2.1.4 available, 2.1.6 latest)

for this rule in bower.json :

    "requirejs": "2.1.1 - 2.1.4",

I was considering adding a test or two too, but I couldn't get the tests to pass even on upstream/master, so I figured I would submit this work for review.