Merge branch 'master' into stable

Fix tabs so that they use the correct id when closing/focusing (onivi…

…m#1761)

* Fix tabs so that they use the correct id when closing/focusing

* Add integration test for opening/closing tabs with tabs.modes set to tabs

Merge branch 'master' into stable

Merge branch 'master' into stable

Merge branch 'master' into stable

Merge branch 'master' into stable

Merge master

Merge branch 'master' into stable

Merge branch 'master' into stable

Revert travis branch change, as it prevents artifacts