TinyMCE not works in Czech language about lms

[chilek]

Try the fix from commit:
6f7da9c

[Vantomas]

Yes, it works. But maybe would be better change language name from "cz" to "cs", because I just found issue with automatic detection with language based on HTTP header Accept-Language.

My web browser send cs-CZ and cs in headers and code in lib/language.php ignores it because don't know something like "cs".
Accept-Language:cs-CZ,cs;q=0.8

In the result I have LMS in English language and I must set language to cz in lms.ini for Czech.

[chilek]

@Vantomas that's good idea! I've changed it according to your suggestion in last commit. Please check if everything went fine. Thanks!