Update experiment.py

Correcting so that term_id and term id go to the same facet and have the same level
Merge pull request #562 from ENCODE-DCC/2507-term_id_fix

Update experiment.py
Change facet name to Library made from
Merge pull request #563 from ENCODE-DCC/2449-library-facet

#2449 Change facet name to Library made from
Use LRUCache correctly (minimal improvement)
Merge remote-tracking branch 'origin/master' into 2514-sort-audits