Initial setup for Russian translation of site (ru)

Provides

* most of the locales (in _config.yml),
* the site root page (index.html), and
* the news.rss file.

Also adapts Rakefile.
Add 'examples' directory (ru)
Complete initial files for :ru branch (ru)
Merge pull request #196 from gazay/ru-translation

Complete initial files for :ru branch (ru)
Remove code example for disabled javascript (ru)
Translate about pages (ru)
Merge pull request #197 from gazay/ru-translation-about

Translate about pages (ru)
Fix typo
Translate community pages (ru)
Merge pull request #198 from gazay/ru-translation-community

Translate community pages (ru)
Initial setup for Vietnamese translation of site (vi)

Provides

* the site root page (index.html),
* the news.rss file, and
* the examples directory

Also adapts Rakefile.
Add vi support for _config.yml
Translate examples and /index.html (vi)
Fix example; add newline (vi)
Translate 'about' and 'downloads' page (vi)
Small fixes on 'about' and 'downloads' page (vi)
Translate 'libraries' and 'security' pages (vi)
Small fixes on libraries page (vi)
Update security page (vi)
fix translation error of zh_cn