Security updates

There are multiple security vulnerabilities that this pull request addresses.

### Rails updates
February 19, 2014 (Rails 3.2.17)
CVE-2014-0082, CVE-2014-0081

December 3, 2013 (Rails 3.2.16)
CVE-2013-6414, CVE-2013-6417, CVE-2013-6415, CVE-2013-4491

October 23, 2013 (Rails 3.2.15)
CVE-2013-4389

### i18n update
December 4, 2013 (i18n 0.6.6)
CVE-2013-4492

### Devise updates
August 6, 2013 (Devise 2.2.5)
CSRF Token Fixation Attacks

March 21, 2013 (Devise 2.2.3)
CVE-2013-0233

### Nokogiri updates
December 27, 2013 (Nokogiri 1.5.11)
CVE-2013-6461, CVE-2013-6460