Don't build oniguruma when croos building or onigiruma is already installed.
Enable already fixed test.
Follow latest mrb_get_args format.
Add ISO no in tests.
Implement `OnigRegexp.quote`.
Implement `OnigRegexp#options`.
Implement `OnigRegexp#initialize_copy`.
Support travis test.
Merge pull request #19 from take-cheeze/etc

Updates.