Started Rewriting Packet Handling

Started rewriting our packet handling code. Deleted PacketHandler in
favor of using sided (Server-, Client-) packet handlers to make it
easier to follow what's going on in our code. Added some event-based
handling of updates which greatly simplified signaling that data needs
to be sent, but it's not completely done yet.

StevenDimDoors/mod_pocketDim/watcher/IOpaqueReader.java

@@ -0,0 +1,8 @@
+package StevenDimDoors.mod_pocketDim.watcher;
+
+import com.google.common.io.ByteArrayDataInput;
+
+public interface IOpaqueReader
+{
+	IOpaqueMessage read(ByteArrayDataInput source);
+}