apart from resolving conflicts:
- added missing docs
- inlined functions that were used in only one location
- updated unit test to support all previews
- fixed a regression that displayed the preview even when there was no preview and too early
* load JS file asyncronously (just HTML5 async attribut)
* add basic support for page template, where it generates the code inside
of a simple div at the top
* added option to turn off QR code support