Updated stlink platform to the new locm3 usb api.
Corrected the led pin for F3 and F4 discovery boards. Needs proper fixing so that it works on all platforms in the future.
Merge pull request #10 from esden/stlink_update

Thank you.  I'm not too concerned about the LED.  Is there any way to reliably detect which stlink hardware we're running on?
Merge branch 'master' into develop

* master:
  Corrected the led pin for F3 and F4 discovery boards. Needs proper fixing so that it works on all platforms in the future.
  Updated stlink platform to the new locm3 usb api.
bump libopencm3