When a customized checkout_success_text is used, that has other elements than `<p>`, the alignment was off. This fixes the alignment for all types of elements, that are a direct child of the thank-you-element `.thank-you > *`.
* Fix caching issues in SASS compilation
* Allow to set a custom page background color
* Allow to disable round corners
* Support larger header pictures
* Allow to show title despite header
* Move language picker
* FIx widget styles