Allow reversed initial sort

[LemonIceScream]

I have a table with a date column that I wish to display initially in descending order. This is not possible because the initialSort function only allows initial data to be sorted in ascending order.

Relevant issue from original library: evancz/elm-sortable-table#9

I believe extending the initialSort function to accept either a Bool, Sorter or a new Order type would be ideal.

Thanks for maintaining this nifty little library!

[coryc5]

@gaul had a PR that implemented this functionality, which could be a good starting point:
evancz/elm-sortable-table#30

[MarkFarmiloe]

There is already a way to initially sort the data by any column either ascending or descending - simply use Table.initialSort to choose the column and set that column's sorter to either Table.decreasingBy or Table.decreasingOrIncreasingBy. The problem imho is with the sort-state arrows in the header. If there is only one sort available, whether that is ascending or descending, it is shown as a down arrow. Similarly if the column can be sorted either way, then the first sort is displayed as a down arrow whether this is descending or ascending. The function that needs changing is toHeaderInfo. I'll shortly do a pull request which you can accept if you agree with me :-)

[billstclair]

Fixed in version 1.1.3 by 959a821 and 01d1e0f.

Thank you to @MarkFarmiloe for doing this.