* support num_flatten_dims=-1 of API fc. test=develop

* fix name of class Test* and add CUDAPlace test. test=develop

* fix PythonAPI test in Op unittest, test=develop
* fix unit tests that do not need to inherit OpTest, test=develop

* Add fc padding to solve mkl performance
test=develop

* fix gpu pass and error information
test=develop

* fix fc_fuse_pass_test
test=develop

* fix error information
test=develop

* fix error information
test=develop

* fix name and add fc op padding test
test=develop

* fix attributes
test=develop

* optimize fc padding
test=develop

* fix test
test=develop

* Add fp16 in input.dtype check test=develop

* Add warning of fp16 in CPU test=develop

* add unittest code for fp16 test=develop

* fix float16 list error test=develop

* add api check in fc test=develop

* enforce shape error info of sum op test=develop

* fix spelling test=develop

* print x_dims info test=develop

* enhance shape error info test=develop

* Refine the codes related to fc op.

* Add GPU implementation for fc functor.

* Apply fc_fuse_pass in GPU inference.
test=develop

* Change the cmake for fc op.

* Change PADDLE_ENFORCE to PADDLE_ENFORCE_EQ.

* Add an attribute to set the activation type in fc_op.

* Enhance the unittest of fc_op.
test=develop

* Remove the declaration of FCOpGrad back to the header file.
test=develop

* Set default value for newly added arguments in test_fc_op.
test=develop