- Add FIXME tags comments to some unfixed potential bugs
- Remove some checks (always false: unsigned never < 0)
- Fix some if statements based on reviews.
- Bunch of missing `else` statements
- `certs` and `editor_fonts` go to `thirdparty`
- `dist` and `scripts` go to a new `misc` folder
- `collada` and `doc` go to `tools/editor`
The next step will be to rename `tools/editor` to `editor` directly,
but this will be done at the right time to avoid breaking too many PRs.