m_spanningtree Sync bursting state of servers in SERVER

Also send the time when they started bursting
m_spanningtree Only mark one server as finished bursting on ENDBURST (or PONG), not all behind it
m_spanningtree Keep track of whether servers are behind a bursting server, use it to implement quietbursts
m_spanningtree Ensure that TreeSocket::Close() is only ran once
m_spanningtree Remove now needless TreeSocket::ConnectionFailureShown
m_spanningtree Move SQuit logic into TreeServer from TreeSocket
m_spanningtree Remove splitting servers from hashes in TreeServer::SQuitInternal()
m_spanningtree Add dead TreeServers to the cull list after quitting the users on them
m_spanningtree Mark dead servers that were split but not yet destructed, add TreeServer::IsDead()
m_spanningtree Quit split users in one go
m_spanningtree Change return type of TreeServers::QuitUsers() to be unsigned
m_spanningtree Use TreeServer::IsDead() to learn whether a user is being quit due to a netsplit in OnUserQuit()
m_spanningtree Remove the now needless SplitInProgress workaround
m_spanningtree Split dead servers as soon as they die, not at the next timer tick
m_spanningtree Throw a ProtocolException if a server SQUITs a server that isn't directly connected to it
Allow fast sid reuse by erasing fake users from the uuid hash in UserManager when they are being split, not in cull
Do not attempt to detect non-culled users at destruction by looking for their uuid, leave it to Extensible

This does not take uuid/sid reuse into consideration and Extensible implements this detection already in a proper way
st landing 5