GR8NET playing wave file from internet and acts as SCC

This is generation 0.1 of the GR8NET adapter based on Altera FPGA chip. It connects MSX computer to the internet, and provides controlled interrupt generator, hardware acceleration function for buffered PCM playback and automated data prefetch from the onboard device (RAM, ROM or W5100). I will be working on the API/system call definition to provide programmers comprehensive development tools basing on the code already existing in the firmware.