This is Pebble's default "Just A Bit" watch face redone without the 10's place, and with flipped (actually flippable with a #define) endian-ness.
Firstly, install the pebble SDK on your computer and ensure it's in your path. Then run
pebble build
pebble install --phone <ip-of-your-phone>
That's it, you should be up and running.
There is one configuration option. Find #define BIG_ENDIAN. Removing this
will flip the bit ordering.