Lazy-require XmlSimple. Move CGI require to object conversions where it's actually used.

activesupport/lib/active_support/core_ext/hash/conversions.rb

 require 'date'
-require 'cgi'
-require 'xmlsimple'
 
 # Locked down XmlSimple#xml_in_string
 class XmlSimple
@@ -168,6 +166,8 @@ def to_xml(options = {})
 
         module ClassMethods
           def from_xml(xml)
+            require 'xmlsimple'
+
             # TODO: Refactor this into something much cleaner that doesn't rely on XmlSimple
             typecast_xml_value(undasherize_keys(XmlSimple.xml_in_string(xml,
               'forcearray'   => false,

activesupport/lib/active_support/core_ext/object/conversions.rb

+require 'cgi'
+
 class Object
   # Alias of <tt>to_s</tt>.
   def to_param
@@ -11,4 +13,4 @@ def to_param
   def to_query(key)
     "#{CGI.escape(key.to_s)}=#{CGI.escape(to_param.to_s)}"
   end
-end
\ No newline at end of file
+end