Add argument to allow constructor to block until valid data has been received.
Add argument to allow constructor to block until valid data has been received.

This slows down initialization, but ensures blocking will not happen later.

Dale reeeeeally wanted this

WPI-ARC/arc_utilities,UM-ARM-Lab/arc_utilities,WPI-ARC/arc_utilities,UM-ARM-Lab/arc_utilities,UM-ARM-Lab/arc_utilities,WPI-ARC/arc_utilities