- Add a dialog to select the exporter
- Export based on exporter id instead of extensions (fix issues like for Collada)
- Message box if there is an error
Some are doxy comments, some are just trivial source comment typos.
Found using `codespell -q 3 --skip="./contrib" -I ../assimp-whitelist.txt`
whereby whitelist contained:
```
childs
iff
lod
nto
ot
whitespaces
```