message: Add icons and tooltips to revisions table headers
diff: <th class='col-md-4'>Version ID</th>
  <th class='col-md-6'>Date</th>
  <th colspan='2' class='col-xs-2'>Download</th>
  - <th class='hidden-md hidden-sm hidden-xs'>MD5</th>
  - <th class='hidden-md hidden-sm hidden-xs'>SHA2</th>
  + <th class='hidden-md hidden-sm hidden-xs'>
  + MD5
  + <i class='fa fa-question-circle'>
  + {{#bs-popover triggerEvents='hover' placement='top'}}MD5 is an algorithm used to verify data integrity.{{/bs-popover}}
  + </i>
  + </th>
  + <th class='hidden-md hidden-sm hidden-xs'>
  + SHA2
  + <i class='fa fa-question-circle'>
  + {{#bs-popover triggerEvents='hover' placement='top'}}SHA-2 is a cryptographic hash function designed by the NSA used to verify data integrity.{{/bs-popover}}
  + </i>
  + </th>
  </tr>
  </thead>
  <tbody>
  