Add InPacket interface and ByteBuf implementation

Replacement for LittleEndianAccessor, SeekableLittleEndianAccessor,
GenericLittleEndianAccessor, and GenericSeekableLittleEndianAccessor.

src/main/java/net/packet/ByteBufInPacket.java

@@ -0,0 +1,79 @@
+package net.packet;
+
+import io.netty.buffer.ByteBuf;
+
+import java.awt.*;
+
+public class ByteBufInPacket implements InPacket {
+    private final ByteBuf byteBuf;
+
+    public ByteBufInPacket(ByteBuf byteBuf) {
+        this.byteBuf = byteBuf;
+    }
+
+    @Override
+    public byte[] getBytes() {
+        // TODO
+        return null;
+    }
+
+    @Override
+    public byte readByte() {
+        return byteBuf.readByte();
+    }
+
+    @Override
+    public short readShort() {
+        return byteBuf.readShortLE();
+    }
+
+    @Override
+    public int readInt() {
+        return byteBuf.readIntLE();
+    }
+
+    @Override
+    public long readLong() {
+        return byteBuf.readLongLE();
+    }
+
+    @Override
+    public Point readPoint() {
+        final short x = byteBuf.readShortLE();
+        final short y = byteBuf.readShortLE();
+        return new Point(x, y);
+    }
+
+    @Override
+    public String readString() {
+        // TODO
+        return null;
+    }
+
+    @Override
+    public byte[] read(int numberOfBytes) {
+        byte[] bytes = new byte[numberOfBytes];
+        byteBuf.readBytes(bytes);
+        return bytes;
+    }
+
+    @Override
+    public void skip(int numberOfBytes) {
+        byteBuf.skipBytes(numberOfBytes);
+    }
+
+    @Override
+    public int available() {
+        return byteBuf.readableBytes();
+    }
+
+    @Override
+    public void seek(int byteOffset) {
+        byteBuf.readerIndex(byteOffset);
+    }
+
+    @Override
+    public int getPosition() {
+        return byteBuf.readerIndex();
+    }
+}