More optimizations

hercules_cg/src/gpu.rs

hercules_opt/src/fork_transforms.rs

hercules_opt/src/gcm.rs

hercules_opt/src/simplify_cfg.rs

hercules_opt/src/utils.rs

juno_samples/rodinia/backprop/src/backprop.jn

juno_samples/rodinia/backprop/src/cpu.sch

juno_samples/rodinia/backprop/src/gpu.sch

juno_samples/rodinia/bfs/src/bfs.jn

juno_samples/rodinia/bfs/src/cpu.sch

juno_samples/rodinia/bfs/src/gpu.sch

juno_samples/rodinia/bfs/src/lib.rs

juno_samples/rodinia/bfs/src/main.rs

juno_samples/rodinia/cfd/src/lib.rs

juno_samples/rodinia/cfd/src/main.rs

juno_samples/rodinia/srad/src/cpu.sch