removed diagnostic

- Added Unit tests for Softmax MKLDNN Forward

Added fix for div by 0 to happen in cross_entropy backward

Conflicts:
	paddle/fluid/operators/CMakeLists.txt

- Cosmetic fixes to SoftMax MKLDNN fluid operator

Added misssing softmax fluid operator file

Disabled MKLDNN softmax operator by default

Fix to softmax op unittest merge

clang_formater fixes

clang_formatter fixes

- Name changing of softmax mkldnn operator to maintin consistency
  across codebase

- updated comment

fix to comment

1. Rename inputs and outputs
2. Add some comments

The error is:

paddle/fluid/operators/math/concat.cc:47:72: error: invalid initialization of non-const reference of type 'paddle::platform::CPUPlace&' from an rvalue of type 'paddle::platform::CPUPlace'
   auto& cpu_place = boost::get<platform::CPUPlace>(context.GetPlace());

Should not use reference for cpu_place.