Removed sipsimple.clients.enrollment module

Ignore-this: 9fd8760a06a5cd8554d9e09a559056c8

darcs-hash:20090329235350-1e3d8-c058021e04201fa9a3b17a26b57deefb1266058a
sip_session: add nat detected message

darcs-hash:20090327143757-b2873-98649e1e4af9bbf7e39d33895e32ec834e29003b