Change board's ready trigger / Ensure attachment of servos

[sevastos]

Thanks for your work ecto, duino is really cool and easy to get into, good job!

Anyway, this PR fixes #21.

It was a sort of racing condition where the board would sometimes trigger the ready event earlier and it should, now it listens for serialport's open event.
Also I made it so that you can use servos inside the board's ready event callback.
Lastly updated the board's name property to path based on serialport's.

Cheers

[chrisatomix]

Something's wrong here, this breaks the device: 'ACM' functionality in lib.board.js that was added here:

1dc1277