Enhance RB.BaseResource to enable uploading multiple files at once.
Review Request #4258 — Created June 24, 2013 and submitted
Enhance RB.BaseResource to enable uploading multiple files at once. BaseResource had a lot of code for handling file uploads through the API, but it only supported uploading a single file per request. This change generalizes that to handle uploading any number of files.
Ran unit tests.
