Merge remote-tracking branch 'origin/master' into 1786-library-spikeins-ui
First pass at assay dataset display

Existing code only displays the first assay. Will next try displaying all of them.
Back out library test data change.
Merge remote-tracking branch 'origin/1786-library-spikeins' into 1786-library-spikeins-ui
Merge remote-tracking branch 'origin/master' into 1786-library-spikeins-ui
Merge remote-tracking branch 'origin/master' into 1786-library-spikeins-ui
Merge pull request #452 from ENCODE-DCC/1786-library-spikeins-ui

1786 UI for assay spikeins display