update changelog

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@1018 65c4cc65-6c06-0410-ace0-fbb531ad65f3

CHANGES

+ -- Add RDNIS support to SIP and IAX2
+ -- Add transfer app (implement in SIP and IAX2)
  -- Make voicemail segmentable by context (app_voicemail2)
  -- Major restructuring of voicemail (app_voicemail2)
  -- Add initial ENUM support