Homework assignment due 11/22

1. Complete the transport layer to support update() and post(), make sure to apply proper policy.
2. When the receiver fails to acknowledge a byte transmission, the i2c_byte_nack_isr() function is called instead of the i2C_byte_recv_isr().
   Complete the code for this function to ensure that the frame is retransmitted. Note: I have modified the on-line version of the code to more clearly distinguish between frames and packets. Now, there is no guarantee that a frame and a packet are the same thing. Please use this version of the code for the homework.