Changes:
- Firework gui behavior has been changed a bit to be more intuitive and easy to use (/ie firework)
- zh (chinese) language has been split into zh_cn.yml and zh_tw.yml, other languages falls under the first 2 characters (both en_gb and en_us falls under en.yml)

Fixes:
- minor errors with placeholders
- middle click can be used on gui only while in creative mode, so now you can also press 1 instead of middle click to use the gui on other gamemodes

Note:
- Configuration updater should fix most of changes of language files but if you didn't customize them i suggest to just delete and regenerate all language files