Fix test_parallel_executor_mnist.py randomly hang.

MKLDNN conv+elementwise_add fusion for residual connections in Resnet

Fea/fusion seqconv eltadd relu

test=develop

test=develop

Add RoI align operator.

MKLDNN conv + elementwise_add fusion: UT for missing bias added. UTs refactored. Some minor changes in the pass

test=develop

test=develop

test=develop

test=develop

test=develop

macro used.

test=develop

MKLDNN conv + elementwise_add fusion: skip connection attribute renamed. Comments about patterns added.

test=develop

MKLDNN conv + elementwise_add fusion: Fix transpiler integration to predict skip connection input of eltwise_add

test=develop

MKLDNN conv + elementwise_add fusion: Fix output_data to point to the right tensor, also fix transpiler integration

MKLDNN conv + elementwise_add fusion: some refactoring: consts, function calls instead of constant values

MKLDNN conv + elementwise_add fusion: graph is corrected based on actual argument name, not formal argument name

MKLDNN conv + elementwise_add fusion: output and elemwise param share data in conv primitive. Output is properly allocated

MKLDNN conv + elementwise_add fusion: inputs in pass modified. Support for new conv parameter. UTs corrected

MKLDNN conv + elementwise_add fusion: added reachability tests, inputs and outputs in graph nodes are transformed