Add while(!Serial) for reliable Serial init

If you don't include `while(!Serial);`, Clyde's serial
port is very very unreliable.  This is due to the fact
that Clyde is based on the Ardunino Leonardo, which shares
USB with serial communication.

Add a Serial output so people know that Clyde is now ready
and willing to accept commands.
Comment out serial ready line for normal operation

Normal operation means not connected to a serial port.

- If you have that line in, Clyde won't start executing until the Serial Monitor is opened (bad)
- If you don't have that line, Clyde starts up and runs just fine.

So, if you want to talk to Clyde,
- If you want to send serial commands to Clyde, you must have that line in your file
- If you don't have that line, serial communications are unreliable
Merge pull request #5 from polastre/hotfix/serial

Add while(!Serial) for reliable Serial init