boost -> std thread, clean up bad merge
boost -> std thread, clean up bad merge

lucadelu/PDAL,Sciumo/PDAL,boundlessgeo/PDAL,mpgerlek/PDAL-old,lucadelu/PDAL,mpgerlek/PDAL-old,Sciumo/PDAL,boundlessgeo/PDAL,DougFirErickson/PDAL,radiantbluetechnologies/PDAL,boundlessgeo/PDAL,DougFirErickson/PDAL,lucadelu/PDAL,mtCarto/PDAL,Sciumo/PDAL,mpgerlek/PDAL-old,radiantbluetechnologies/PDAL,mpgerlek/PDAL-old,DougFirErickson/PDAL,boundlessgeo/PDAL,mtCarto/PDAL,lucadelu/PDAL,jwomeara/PDAL,DougFirErickson/PDAL,radiantbluetechnologies/PDAL,mtCarto/PDAL,jwomeara/PDAL,mtCarto/PDAL,jwomeara/PDAL,jwomeara/PDAL,Sciumo/PDAL,radiantbluetechnologies/PDAL