[draft] a simple op design doc

Add tensor.h

Fix bug for flowers dataset and row_conv.

fix input shape of train_y in get started doc

Design doc: save model in cluster training.

ENH: support command `make target_name`

fix the bug of copy master directory.

NNPACKConvFunction

FIX: Replace static libs check via system warning

Add the use_nnpack parameter in ExpandConvLayer, so that the convolution calculation can be switched to the NNPACK function.

Design doc for go package management

FIX: Always build protobuf from source

ENH: Remove deprecated python build

Improve Go cmake, add go/master/c into cmake include path..

FIX: merge objects to static lib

fix bugs

add more choice for eigen downloading

enable users to set intial memory states for lstm/gru group.