Suite name with hyphen fix

[avant1]

This allows to use suites with hyphen in name in --suite CLI option.

Fixes #968.
I've included work from #969, but moved scenario to another feature file.

BTW this is a potential BC break for users who had hyphens in suite names and who used underscored version of names in --suite filters.
With this PR --suite=some_suite will not work if suite has name some-suite.

However, this is a bugfix, and using underscored names was not documentated anywhere.

[everzet]

Thank you very much for contribution!