Update locales/cs/strings.js

I will not be probably continue until tomorrow. 

PS:
I am experiencing some problem with "superbar" translation... You are using it for something what I don't know from day to day using (this option I have disabled but I saw it before) but you are not using it like windows for its  w7 - superbar (taskbar). In Czech we don't have any similar word(s) for it so I let it as it is (super is "great, nice" and "bar" is "bar") but this could be terminus technicus contra-production in English language and also in Czech...