Run json-schema.org's common test suite
Init/update submodule as required
Switch to inferior indent scheme
Display *why* a common-test-suite test failed

This is good, because it's easier to debug a problem if you know *why*
there's a problem.
Skip tests that we know fail, rather than not defining them

As suggested by @pd.
Merge pull request #122 from mpalmer/common-test-suite

Run json-schema.org's common test suite