Update Language/locale/cz.js

Correcting date and time formats (no comma separating month and year, no AM/PM, "at" –> "v"). n-dash in year ranges without spaces (e.g. 1900–1910 instead of 1900 - 1910) would be highly desirable as well
Merge pull request #9 from pethr/patch-1

Update Language/locale/cz.js