delete alias:
  url
delete filter:
  alias, subset of filter keywords
  by default only allow one row to be deleted
  delete --all flag allows to delete more than one filter at a time


option to use cookies when downloading feeds
  per feed? file? or values?
  would need to add ability to update feed cookies if not in a file


probably will never do:
in update inner loop, add option to use lastBuildDate instead of pubDate
add verbose flag to list filters command to show full script path