change perform_all response format
If test failed, raise
Merge pull request #33 from sue445/feature/failure_exit_status

Feature/failure exit status
Refactor runner
silence logging in test
Merge pull request #34 from sue445/feature/refactor_runner

Feature/refactor runner
tweak yard
rename
Add prefix
:put_litter_in_its_place:
tweak yard
Merge pull request #35 from sue445/feature/refactor

Feature/refactor
Add changelog [ci skip]
Tweak gemspec doc [ci skip]
[WIP] Write usage [ci skip]