Merge pull request #94 from codalab/pliang

better output for cl run
Merge pull request #99 from codalab/pliang

consolidate second-pass lookup of values inside files to server call interpret_file_genpaths
allow (sub)worksheets to be worksheet items, and resolve worksheet references based on the current worksheet; requires a database migration, changes BundleClient API so that we can resolve worksheets relatively and get info about them without fetching their items
fix wcp bug (now don't copy worksheets)
guard against non-existent bundles
fix -f args bug
quote command
sort dependencies alphabetically
Merge pull request #102 from codalab/pliang-hierarchical-worksheets

allow (sub)worksheets to be worksheet items, and resolve worksheet refer...
allow display table to take in multiple schema names