(it) update security page

with the latest security news, links to en page for older news. Sync text with en..
more speed-up on travis deployment
Update download page translation (it)
Translate mirror sites countries (it)
Merge pull request #420 from alepore/it-security-translation

(it) update security page
Merge pull request #405 from kennyadsl/fix-download-page-it

Update download page translation (it)
Fix typos and link on downloads page (it)
Mark email field in subscription form as required
Split design credits into separate paragraph
Update credits (de)
Fix missing newlines at end of file
Mark ko as unmaintained
Fix link on downloads page
Fix typos (zh_tw)
Make header levels match 'en' version (zh_tw)
Fix heading level of references on about page
Fix list markdown on about and success-stories pages

Do not start a new list for every list item.
Adopt libraries page examples from 'en' (zh_tw)
Update gem bundle
Clean up and update links on libraries page (en)