Changes since 2.3.5:
* HTML safety: fix compatibility with the optional rails_xss plugin.
[Nathan Weizenbaum, Santiago Pastorino]
* 1.9 compat: deprecated last_(month|year) in favor of
prev_(month|year). [fxn]
* Deprecated Array#rand in favor of Array#random_element. [Santiago
Pastorino, Rizwan Reza]
* Added Object#presence that returns the object if it's #present?
otherwise returns nil [DHH/Colin Kelley]
* New assertions assert_blank and assert_present. #4299 [Juanjo Bazan]
* Use Object#singleton_class instead of #metaclass. Prefer Ruby's
choice. [Jere my Kemper]
* JSON backend for YAJL. Preferred if available. #2666 [Brian Lopez]
* Introduce String#html_safe for rails_xss plugin and
forward-compatibility with Rails 3. [Michael Koziarski, Santiago
Pastorino, José Ignacio Costa]
* Time#- with a DateTime argument behaves the same as with a Time
argument, i.e. returns the difference between self and arg as a
Float #3476 [Geoff Buesing]
* YAML serialization for OrderedHash. #3608 [Gregor Schmidt]
* Add Enumerable#exclude? to bring parity to Enumerable#include? and
avoid if !x .include?/else calls [DHH]
c4230236a6