Allow recreation of invalid or broken content.
Specifying language code is now required when getting library translations. The library loading function will also try to find content language.
Made it possible to select no value in select list.
Use default values.
Merge branch 'without-pal' of github.com:h5p/h5p-editor-php-library into without-pal
Merge branch 'without-pal' into css-mods