test harness for RDF test suites

Dear all,

for those who attended the WG call today, this is the project I mentioned.

https://github.com/pchampin/sophia_testing

The executable |sophia-tests| has two purpose:

  * test the |sophia| <https://crates.io/crates/sophia> library against
    the test suites of the relevant W3C <https://www.w3.org/> standards,
  * allow for other tools to be tested against the same test suites, via
    a command-line hooks.
  * In both cases, it produces an EARL report
    <https://www.w3.org/TR/EARL10-Schema/> with the results.

It might be useful for other implementers -- or to test somebody else's 
tool :)

   enjoy