[PASS] PrintGraphIR, SimplifyBatchNormInference (#19)

nnvm/include/nnvm/node.h

nnvm/python/nnvm/compiler/graph_attr.py

nnvm/python/nnvm/compiler/graph_pass.py

nnvm/python/nnvm/graph.py

nnvm/python/nnvm/top/nn.py

nnvm/src/compiler/graph_deep_compare.cc

nnvm/src/compiler/graph_fuse.cc

nnvm/src/compiler/graph_transform.h

nnvm/src/compiler/layout_transform.cc

nnvm/src/compiler/node_attr.h

nnvm/src/compiler/packed_func_ext.cc

nnvm/src/compiler/precompute_prune.cc

nnvm/src/compiler/simplify_batch_norm.cc

nnvm/src/pass/print_graph_ir.cc

nnvm/src/top/nn/nn_common.h

nnvm/src/top/tensor/elemwise.cc

nnvm/tests/python/compiler/test_graph_pass.py

nnvm/tests/python/compiler/test_simplify_batchnorm.py

nnvm/tests/python/unittest/test_top_level1.py