Add InPacket interface and ByteBuf implementation

Replacement for LittleEndianAccessor, SeekableLittleEndianAccessor,
GenericLittleEndianAccessor, and GenericSeekableLittleEndianAccessor.

src/main/java/net/packet/InPacket.java

@@ -0,0 +1,17 @@
+package net.packet;
+
+import java.awt.*;
+
+public interface InPacket extends Packet {
+    byte readByte();
+    short readShort();
+    int readInt();
+    long readLong();
+    Point readPoint();
+    String readString();
+    byte[] read(int numberOfBytes);
+    void skip(int numberOfBytes);
+    int available();
+    void seek(int byteOffset);
+    int getPosition();
+}