Use BlockCommandSender for dispatching Command block commands

Also allow commands that don't start with a / to match vanilla behavior

By: Travis Watkins <amaranth@ubuntu.com>

paper-server/src/main/java/org/bukkit/craftbukkit/command/CraftBlockCommandSender.java

@@ -0,0 +1,42 @@
+package org.bukkit.craftbukkit.command;
+
+import net.minecraft.server.TileEntityCommand;
+import org.bukkit.block.Block;
+import org.bukkit.command.BlockCommandSender;
+
+/**
+ * Represents input from a command block
+ */
+public class CraftBlockCommandSender extends ServerCommandSender implements BlockCommandSender {
+    private final TileEntityCommand commandBlock;
+
+    public CraftBlockCommandSender(TileEntityCommand commandBlock) {
+        super();
+        this.commandBlock = commandBlock;
+    }
+
+    public Block getBlock() {
+        return commandBlock.world.getWorld().getBlockAt(commandBlock.x, commandBlock.y, commandBlock.z);
+    }
+
+    public void sendMessage(String message) {
+    }
+
+    public void sendRawMessage(String message) {
+    }
+
+    public void sendMessage(String[] messages) {
+    }
+
+    public String getName() {
+        return "@";
+    }
+
+    public boolean isOp() {
+        return true;
+    }
+
+    public void setOp(boolean value) {
+        throw new UnsupportedOperationException("Cannot change operator status of a block");
+    }
+}