Added state notifications to AccountManager

Ignore-this: 82924d50c7a2d33221b6344002e1c15

darcs-hash:20090715094150-1e3d8-0c2dc3144ffa252cb2ac96785129d1549c335c77
Fixed creation of FrozenRetryAfterHeader

Ignore-this: 34ef149235076a706af81170903f2308

darcs-hash:20090715134515-1e3d8-bb7d1089cf22e395a82e1bf4366d63863196e7c9