Re-wrote baud menu system.

Now supports any baud rate from 300bps to 1,000,000bps and anything in
between. This will allow you to really configure OpenLog to anything you
need, but remember you can always hardware reset OpenLog to 9600 by
pulling the RX line low during power up.
Added ability to ignore RX.

You can now ignore the state of RX at power up. See issue #150.