remove outdated selenium tests which were never executed recently.

These tests were created using Selenium's test recorder so they are basically unmaintainable.
remove dummy "functional" test cases (WebTest-based).

These tests were not executed for quite some time and they don't
test anything (besides issuing a request to a certain controller)
remove MediaCore CE copyright header from htmlsanitizer. The (now removed)
copyright header was obviously added by accident during the big "frontend
JS MIT relicensing" in early 2012.

The file contents are licensed under a "simplified BSD license"
l10n/it: updated some missing translations
l10n: recompile Italian catalog