Common error handling
Would be nice to catch and prevent common issues:
- Title conflicts. when two icons share the same title, only one gets exported.
- Objects with strokes. we are no longer able to export those sometimes the misrendering is hard to spot.
- List/log unexported assets. While it's desirable to keep assets aournd in the canvas that aren't to be exported, many times some overlays are mistakenly kept outside of the export group