Encourage users to install the ruby-full meta-package.

* This will also install ruby-dev, which is needed for compiling any C
  extensions.
Emphasis installing ruby from the package manager.

* Most users just need a Ruby so they can run sass or jekyll.
  Whereas RVM/rbenv are more suited for developers and power-users.
Organize in-page links by installation method than by platform/tool.

* Combined the Package Management Systems sub-list into the top list.
Split the "Third party tools" section into "Installers" and "Managers".
Added ruby-build and ruby-install to the Installers section.
Added chruby to the Managers section.
Put Installers before Managers.
Add a summary to the Installers section.
Link to the chruby section.
upgrade jekyll2
removing to deprecated option
Consistently use `highlight sh' instead of `highlight bash'
Use `irb' Pygments lexer in 2.1.4 news post
Use `irb' Pygments lexer on ruby-from-other-languages page
Use `irb' Pygments lexer on quickstart page
Translate release news from 10/27 (es)
Merge pull request #877 from dabit/master

Translate release news from 10/27 (es)
Small fixes in news posts (es)
Translate changing default setting of ext-openssl post (vi)
fix incorrect words