I limited the columns for 'files', 'replicates' and 'libraries' collections.
Had to make small change to make all the test work!
Added few more columns on Ben's request!
Handle missing biosamples on experiment page, closes #788.
Merge pull request #35 from ENCODE-DCC/r2-hotfix-785

R2 hotfix #785
Merge pull request #36 from ENCODE-DCC/renderless-experiment-788

Handle missing biosamples on experiment page, closes #788.