Convert two getNodeInfo functions to using a new class"

Hello @nicks, 

It looked like `getNodeInfoFromInput` returned the same schema, so I converted that as well.

Please review the following commits I made in branch 'kylehardgrave-return-class'.

eda0cfddccfde474686f1cb3d42ab85a65b29f8c (2013-06-05 17:04:19 -0700)
Have getNodeInfoFromModifier also use the new class object

ad7b410b08990cc00d7d312d827f3a4e08a8dfbf (2013-06-05 16:59:52 -0700)
Have getNodeInfoFromInput return a class object


R=nicks