Move editor color schemes to resource files

* Using json format which can be easily read by boost
* Files are enumerated so it's possible to drop additional files into the resource folder
* Uses properties ```name``` as display name and ```index``` for sorting in GUI
* Get scheme list from editor so the legacy editor shows only the known color schemes

ToDo:

- [ ] validate colors (especially brace selection and highlight color)
- [ ] check Linux build
- [ ] check MacOS installer
- [ ] check Windows installer