Add a :limit option to specify the maximum number of records that can be processed by accepts_nested_attributes_for

Store entire options hash in the class var rather than just the reject_if proc for the nested attributes

Signed-off-by: NCarl Lerche <carllerche@mac.com>

Ruby 1.9: Fix ActiveResource::ConnectionError#to_s when @response does not respond to #code or #message
Signed-off-by: NCarl Lerche <carllerche@mac.com>

Conflicts:

	activerecord/lib/active_record/nested_attributes.rb

  This consists of:

  * String#html_safe! a method to mark a string as 'safe'
  * ActionView::SafeBuffer a string subclass which escapes anything unsafe which is concatenated to it
  * Calls to String#html_safe! throughout the rails helpers
  * a 'raw' helper which lets you concatenate trusted HTML from non-safety-aware sources (e.g. presantized strings in the DB)
  * New ERB implementation based on erubis which uses a SafeBuffer instead of a String

Hat tip to Django for the inspiration.

Signed-off-by: NCarl Lerche <carllerche@mac.com>

Signed-off-by: NJoshua Peek <josh@joshpeek.com>

Allows separate models that include ActiveModel::AttributeMethods to
use different sets of attribute matchers.
Signed-off-by: NJoshua Peek <josh@joshpeek.com>

Cloned AR objects are now instantiated through initialize_copy rather than
new/initialize. This allows AR classes to override initialize_copy in order to
implement deep cloning.
Signed-off-by: NJoshua Peek <josh@joshpeek.com>

Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>