Adding support for core based reservations

src/plugins/sched/backfill/backfill.c

src/plugins/sched/builtin/builtin.c

src/plugins/sched/wiki2/job_will_run.c

src/plugins/select/bluegene/select_bluegene.c

src/plugins/select/cons_res/job_test.c

src/plugins/select/cons_res/job_test.h

src/plugins/select/cons_res/select_cons_res.c

src/plugins/select/cray/other_select.c

src/plugins/select/cray/other_select.h

src/plugins/select/cray/select_cray.c

src/plugins/select/linear/select_linear.c

src/scontrol/create_res.c