Sorting improvements

[aarondr77]

Removing sort from column

When you sort a column, there is no way to identify which column has the sort applied to it and there is furthermore, no way to remove that sort once the column control panel is closed. Reopening it doesn't reapply the state to the sort buttons.

Sorting based on multiple columns

TODO

[naterush]

I think that there's some more specification work needed to say what this even means. Imagine the follow sequence of events:

1. Sort column A.
2. Sort column B.
3. Go back and remove sort on column A.

What is the final state of the dataframe? Is it just the sort on B? In which case what does removing the sort on A even mean?

I think we should approach this in the same step as a multi-sort step, thinking about how the sort relates to the current state of the sheet. So updated this issue to reflect that!