add tests: URL's with non-ascii names....

Want some tests that will prevent regressions on:

* https://github.com/MetPX/sarracenia/issues/884

* a few file names with UTF-8 accented characters in them.
* others with + in them (case from 884)
* perhaps a colon or two.

encodings to worry about:
* url-encoding
* character encodings (utf8 vs. iso8859-1 vs. ascii)

The issue does not name a test file or entry point. Start by reviewing the existing test cases in sr_insects and the linked sarracenia issue #884, then identify how tests cover URL encoding and character encodings. Done means regression coverage for UTF-8 accented names, plus signs, colons, and the relevant encoding variants.

Written by the indexing model from the issue text.