xv11_driver_node: begin rewriting xv11_driver in C++
xv11_driver: c version now publishes LaserMeasurements (LaserScans in progress)
xv11_driver_node: finish rewriting xv11_driver in C++; let's see how it works
xv11_driver_node: remove LaserScanWrapper struct, rearrange the node handles
Merge branch 'master' into xv11_c to bring in Jacob's work before merging back to master