Do not allow underscores in option names. Closes #2391
Make test and test cases exit with reason :shutdown

This guarantees OTP processes are properly shutdown when
the test finishes.
Merge pull request #2397 from alco/option-parser-fix

Do not allow underscores in option names. Closes #2391
Disambiguate (w)erl to (w)erl.exe
Merge pull request #2399 from chyndman/win-disambiguate-exe

Disambiguate (w)erl to (w)erl.exe