removed another unnecessary boost library dependency
removed another unnecessary boost library dependency

shaunharker/DSGRN,breecummins/DSGRN,shaunharker/DSGRN,shaunharker/DSGRN,breecummins/DSGRN,shaunharker/DSGRN,breecummins/DSGRN,breecummins/DSGRN,goullet/DSGRN,breecummins/DSGRN,breecummins/DSGRN,breecummins/DSGRN,shaunharker/DSGRN,shaunharker/DSGRN,goullet/DSGRN,goullet/DSGRN,goullet/DSGRN,goullet/DSGRN,shaunharker/DSGRN,goullet/DSGRN