Merge branch 'onboarding-dialog-style' into 'master'

Introduce Dialog Theme for Onboarding

Currently onboarding dialogs and confirmation dialogs look the same. This MR introduces a new dialog theme for onboarding dialogs that looks like the tap target onboarding, so that the user can immediately spot the purpose of the dialog.

![device-2016-12-06-085539](/uploads/6d75b17c0f20028bb7ffac65e6fba03a/device-2016-12-06-085539.png)

See merge request !446