Valkyrie single sided surface mount stepper board

Re draw of Tinhead's Valkyrie stepper motor board (V2.7)to use surface mount parts in a single sided board to make it easy to fabricate yourself.

This uses I2C to communicate with the main board
(see; http://letsmakerobots.com/node/9006)

Because it is surface mount I added an isp header to allow programing
and just for fun I added a ftdi header.
I also added a second I2C header to allow easy daisy chaining of stepper boards.