- Added new EasyStyler functionality:
   - No more prefixes needed, i.e. -transform => use transform
     we now use a prefixed lookup table to generate -webkit-transform etc.
   - dashes within styles will now work from js: e.g. user-select or userSelect
     will now both work although the first is in principle the css-syntax only.
- Removed obsolete _dataId (only use the DOM value).
- Use protected member for Points and Vectors (avoids a getter/setter)