mega2560 serial port changes + github

[bruce33]

Thanks for the great port, I'm enjoying using it on the mega2560. I've put the 750 release of code in github and made a couple of very small additions/changes to cope with the extra serial ports on the mega2560, and one small bug fix when I had noise on a serial line causing the device to run slow/lock up.

Would you consider putting any future releases on github?

[Phillip Stevens]

Bruce33,
thanks for the support.

Actually, I have already put avrfreertos on github.
https://github.com/feilipu/avrfreertos

But unfortunately I didn't have the time to learn the whole git commit / pull / push thing properly, so I haven't maintained it well.

I'll be working on the new freeRTOS v8.0.0 version over the next few weeks, and perhaps I can have another go with git...