Update Circuit_07.ino

Fixing baud rate to character conversion.

The serial port is operating 9600 bits per second and the Arduino uses [8-N-1 by default](http://arduino.cc/en/Serial/Begin). So if each single-byte character is 10 bits, by my calculation, it's transferring 96 characters per second. I'm guessing it's just a typo.

I'm enjoying my SIK. Thanks.