changes for codalab website

The biggest change here is adding interpret_items_and_file_genpaths to the remote bundle client. 
With this commit on codalab site. 
https://github.com/codalab/codalab/commit/cbc80b14f6c4eee8ff0f9b4e9a70d12e4fca6e1e

This allows a single call to client via RPC to interpret items and any file paths and other things that the client might need to do. 

Also a deep copy on bundle_infos so that each item has ref to it's metadata. Was returning blank before to codalab site. 
Also, please add a comment on what this function does.