Comment 11 for bug 1660142

I just attached
- the updated "part1": This simply fixes the crash issue. There was still a logic error in the previous example (which was not exposed, though) which is fixed now.
- a complete "part2": Includes the small fix from "part1" and attempts to load resources from "file:" URIs even if they are not completely standard-conformant.

While working on "part2" I also noticed some issues in the resource-manager.cpp that should be fixed now:
- typo in a Glib::file_test that probably made Inkscape re-evaluate relative references
- fixed paths where not always properly converted to relative paths.

I'd suggest to push "part1" to the 0.92.x stable branch (it's an easy enough fix it shouldn't cause any regressions) and what is now "part2" to trunk (I guess the issues fixed are not important enough to justify backporting / risking regressions?)