Change the layout of the Players index page to match that of the Team show page. Use tabs for "this season"
and "last season" scores, although these tabs are not JavaScript driven and still fetch the page again,
because of the complexity issues of maintaining the sort orders.
Use a helper function to format the Team Cash number for display instead of repeated code.
When adding or dropping a player, use AJAX to update the Team Cash display dynamically. Fixes #4.