stm32:l0: miniblink example

REQUIRES UNMERGED LIBRARY!
Draft for inspection only!
From my quick read of the nucleo docs, the "arduino d13" led is PA5, like the red led on the disco board, and PB4, the green led on the disco board is also broken out, so should have worked on the nucleo board too.  The OOCD_ definitions here though are just to make "make flash" work.