Fix sorting behavior and add tooltips

Prior to this change, when you would sort, the first time you'd sort on any field, it would sort by ascending. Then, if you sorted on a different field, it would swap to descending (instead of always sorting first by ascending, then by descending).

This change also adds tooltips for the controls that allow you to sort and move columns in tables. It also changes the default icon when sorting from the `fa-sort` to the `fa-sort-up`, in an attempt to communicate to the user that clicking on the field will sort first by ascending and avoid confusion. (See #2112.)

Closes #2112.