message: Add catch all error handling in case of AJAX fail response
  Add `fail` block to form submission request promise chain.
  Add timeout tracking so that old requests dont clear timeouts set by subsequent requests.
diff: @@ -8,9 +8,13 @@ module.exports = ($el) ->
  $submit = $el.find '.js-submit'
  $errors = $el.find '.js-errors'
  + submissionTimeout = null;
  +
  $form.on 'submit', (e) ->
  e.preventDefault()
  + submissionTimeout && clearTimeout(submissionTimeout);
  +
  serializer = new Serializer $form
  label = $submit.text()
  @@ -31,7 +35,7 @@ module.exports = ($el) ->
  .prop 'disabled', false
  .text 'Sent!'
  - setTimeout (-> $submit.text label), 2500
  + submissionTimeout = setTimeout (-> $submit.text label), 2500
  track.submit 'Invitation sent from user'
  @@ -47,9 +51,26 @@ module.exports = ($el) ->
  .prop 'disabled', false
  .text 'Error'
  - setTimeout ->
  + submissionTimeout = setTimeout ->
  $submit.text label
  $errors.empty()
  , 5000
  track.error 'Invitation not sent, try again.'
  +
  + .catch ->
  + $errors
  + .show()
  + .html """
  + Something went wrong, please contact <a href='mailto:info@are.na'>info@are.na</a> if the problem persists.
  + """
  +
  + $submit
  + .prop 'disabled', false
  + .text label
  +
  + submissionTimeout = setTimeout ->
  + $errors.empty()
  + , 15000
  +
  + track.error 'Invitation not sent: server error. Try again.'
  