Update index.md

mostly的翻译由“只要”改为“主要”，并修改部分词语让句子更通顺。
Replaces & x &amp;
Replaces cellspacing='0' cellpadding='0' border='0' x css alternatives
Adds css for #subscriptions-form table
Fix typos
translated release announce of russian-translation
Translate Russian Translation (zh_tw).
Merge pull request #401 from evilexp/patch-1

Fix typos (ru)
Merge pull request #389 from jazzi/master

Update index.md
Merge pull request #387 from murtra/html_fixes

Html fixes
HTML fixes (replace '&' by '&amp;')
Move credits from 'footer.html' into separate file
Rename 'footer.html' include file to 'languages.html'
Merge branch 'footer-includes'
tiny fix
Merge pull request #402 from hsbt/translation-ru-released

(ja) translated release announce of russian-translation
added .travis.yml