Minor fixes in message parsing in Subscription

darcs-hash:20090717162309-58103-a7054e00f6766de9ce1f79441d34a72a7878962a
Use PJSIP patch to parse Allow-Event header in core

darcs-hash:20090717162748-58103-c37f71f4a99f39eb8a84b7c19099d2b27bbeac46