add mustard.js test for ES6 [SCT-820]
add mustard.js test for ES6 [SCT-820]

briehl/kbase-ui,eapearson/kbase-ui,eapearson/kbase-ui,eapearson/kbase-ui,kbase/kbase-ui,briehl/kbase-ui,briehl/kbase-ui,eapearson/kbase-ui,kbase/kbase-ui,kbase/kbase-ui,kbase/kbase-ui,eapearson/kbase-ui,kbase/kbase-ui