v1.2.0

Added

• Every table section collapses. A year with disposals, dividends, rewards and fund
  holdings in it can be folded down to its headings. The export button sits outside the
  toggle, so clicking it no longer collapses the section under it.
• Sortable table headers. Click any header to sort; click again to reverse. Amounts,
  quantities and dates start at the big end, so one click on Result gives the biggest gains
  and a second gives the biggest losses. Text columns start alphabetically. Rows with nothing
  in the sorted column stay at the bottom either way, rather than sorting as if they were 0.
  Applies to disposals, dividends and rewards, fund holdings and the ISK account table.
• The ISK account table now sits in a section of its own with a caption, like every other
  table, and its empty state matches the rest of the page.