function showOpenSeed (opts) {
  setTitle(opts.title)
  const selectedPaths = dialog.showOpenDialogSync(windows.main.win, opts)
  resetTitle()
  if (!Array.isArray(selectedPaths)) return
  windows.main.dispatch('showCreateTorrent', selectedPaths)
}
Pops up an Open File dialog with the given options.
After the user selects files / folders, shows the Create Torrent page.