CLC-2042 - DASHBOARD: Show the state of the scheduled, unscheduled, completed buttons & add ARIA tabpanel
https://jira.media.berkeley.edu/jira/browse/CLC-2042

Also DRY'ed it up and gave some better naming to items.
Merge pull request #1302 from christianv/CLC-2042

CLC-2042 - DASHBOARD: Show the state of the scheduled, unscheduled, completed buttons & add ARIA tabpanel