Clarify cClientHandle, cPlayer ownership semantics

+ A cPlayer, once created, has a strong pointer to the cClientHandle. The player ticks the clienthandle. If he finds the handle destroyed, he destroys himself in turn. Nothing else can kill the player.
* The client handle has a pointer to the player. Once a player is created, the client handle never outlasts the player, nor does it manage the player's lifetime. The pointer is always safe to use after FinishAuthenticate, which is also the point where cProtocol is put into the Game state that allows player manipulation.
+ Entities are once again never lost by constructing a chunk when they try to move into one that doesn't exist.
* Fixed a forgotten Super invocation in cPlayer::OnRemoveFromWorld.
* Fix SaveToDisk usage in destructor by only saving things cPlayer owns, instead of accessing cWorld.

src/Protocol/ChunkDataSerializer.cpp

@@ -74,7 +74,7 @@ cChunkDataSerializer::cChunkDataSerializer(const eDimension a_Dimension) :
 
 void cChunkDataSerializer::SendToClients(const int a_ChunkX, const int a_ChunkZ, const cChunkData & a_Data, const unsigned char * a_BiomeData, const ClientHandles & a_SendTo)
 {
-	for (const auto Client : a_SendTo)
+	for (const auto & Client : a_SendTo)
 	{
 		switch (static_cast<cProtocol::Version>(Client->GetProtocolVersion()))
 		{
@@ -133,7 +133,7 @@ void cChunkDataSerializer::SendToClients(const int a_ChunkX, const int a_ChunkZ,
 
 
 
-inline void cChunkDataSerializer::Serialize(cClientHandle * a_Client, const int a_ChunkX, const int a_ChunkZ, const cChunkData & a_Data, const unsigned char * a_BiomeData, const CacheVersion a_CacheVersion)
+inline void cChunkDataSerializer::Serialize(const ClientHandles::value_type & a_Client, const int a_ChunkX, const int a_ChunkZ, const cChunkData & a_Data, const unsigned char * a_BiomeData, const CacheVersion a_CacheVersion)
 {
 	auto & Cache = m_Cache[static_cast<size_t>(a_CacheVersion)];
 	if (Cache.Engaged)