Fix client disconnect from leftover socket recv timeout

Clear the 5-second SO_RCVTIMEO that was set during the connection
handshake but never removed. The timeout persisted into the game
session, causing the client to disconnect whenever the server paused
for longer than 5 seconds (e.g. autosave, chunk I/O).

Also update README with chunk unloading and connection stability fixes.

Minecraft.Client/ServerChunkCache.cpp

@@ -927,6 +927,7 @@ bool ServerChunkCache::tick()
 						int ix = chunk->x + XZOFFSET;
 						int iz = chunk->z + XZOFFSET;
 						int idx = ix * XZSIZE + iz;
+						delete m_unloadedCache[idx];
 						m_unloadedCache[idx] = chunk;
 						cache[idx] = nullptr;
 					}