+ - added 'void' action, patch from Yuri V. Mkrtumyan
+ <yuramk@novosoft.ru>
+ - allow "Post Authorize" with order_number but no card info, patch
+ from Paul Zimmer <AuthorizeNetpm@pzimmer.box.bepress.com>
+ - Don't require "check_type" field
+ - s/x_Bank_Account_Name/x_Bank_Acct_Name/ for ACH transactions
+ From Daemon Hughes <daemmon@daemmonhughes.com>:
+ - add "transaction key" (x_Tran_Key) authentication in addition to
+ password
+ - add "recurring_billing" field
+ - added "md5" method
+ From valerian <valerian2@hotpop.com>:
+ - Added "avs_code" method
+ - Return "order_number" for unsucessful transactions also