SVG export
- pattern strokes
- text
- for text on path: when on path shape 
    -> path data into defs
    -> path shape with use on defs path data
    => maps back to text on path shape when importing

SVG import
- fix text
- embedded svg elements
- visibility
- text on path shape -> see above for export
- pattern strokes
- clipping, masking
- filters
- css styling
