* simplify fuse process.

* update from upstream

* close the kernels not empty checker.

* add conv2d, pool2d op and kernels test=develop

* test mobile ci
test=develop

* update

* add elementwise_add kernel
test=develop

* add elementwise_add unit test
test=develop

* enable arm neon
test=develop

* remove Repetitive funcs
test=develop

* fix lite compile

test=develop

* update

test=develop

* add the pattern matcher logic. test=develop

* update op_info usage. test=develop

* add concat op, kernel and unitest test=develop

* enable reshape&reshape2 op and add unit test

* enable scale op and add unit test

* fix XShape checking for reshape2 unit test
test=develop

* remove op_desc.hasInput(..) and op_desc.hasOutput(..) to adapt X86 platform
test=develop

* remove target() and precision() from softmax, reshape, reshape2 and scale op
fix CopyDataFrom() of TensorHvy
test=develop

* alloc memory then copy tensor's data during invoking TensorHvy::CopyDataFrom(...)
test=develop

* fix conflicts

* fix kernel registry realted bugs test=develop

* add android emulator document
test=develop

* add armlinux docker document

* Error modifying document format
test=develop

* enable armlinux compile

* fix deps and skip some build

* update doc and script

* add android simulator

test=develop

* arm linux docker and mobile doc

* update

* enable softmax op and add unit test

* move softmax sub-functions to softmax.cc, and move basic math functions to funcs.h

* migrate several ops:
  mean,
  mean_grad
  fill_constant
  square_grad
  elementwise_sub_grad
  mul_grad

* add sdg_op

* fix kernel platform registration issue

* code cleanup

* fix platform typo

* add fc unit test

* refine eigen fc
add cpu info, arm context
init packed sgemm

* enable packed sgemm

* add arm math

* pass fc ut

* follow comments

* code clean - refine ARM

cmake enhancement:

- add lite_cc_library and lite_cc_test

code clean:

- remove ARM feed and fetch kernels, reuse the Host's

remove unnecessary comments