update: Fixed wrong prepareToobarButton call

* Fixed a wrong prepareToobarButton call that caused the
  `partner_query_addition` variable to remain undefined and thus also
  caused the URLs comming from the popup to look like `queryundefined`.

Signed-off-by: mr.Shu <mr@shu.io>
update: Replaced window.open with tabs in AskDax

* window.open caused problems in new versions of firefox, mostly because
  it triggered the popup detection and fored the user to allow popus for
  duckduckgo.com

Signed-off-by: mr.Shu <mr@shu.io>