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

[petersilva]

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)