One more TODO.
Dirty dirty, but works!  For individual files.
Added tentative README to tests/
Mutualised code and rationalised structure a little bit in run.lua
Correct handling of command-line options in run.lua
Removed one useless test.
Better formatting of error report.
Cleanup.
Cleaned up one more line.
Added skip in hyphenation test to force first word to be hyphenated with XeTeX; updated ref output.
Forcing U+2019 to have a non-zero \lccode (not the case in XeTeX).
Cleanup in run.lua