stride should be int64_t, not int

* delete unused IsNetOp() and Rename()

* rm OperatorBase::Rename implementation

* delete Operator::InputVars()

* remove unused OperatorBase::ShareLoD; ShareLoD has been implemented in infershape

* organize operatorbase; remove unused set_type

* add comments

* fix comment

* Fic CPPLint issues with data_transform

* Fic CPPLint issues with prune.cc

* remove share lod; it has already been performed in infershape

* slightly release test bound of test_image_classification

* fix

* nv_library

* add with_gpu

* revert

* Fix CPPLint issues in init

* Fix compilation

* Fix typo in init.cc

* Fix CPPLint issues in library_type.h

* Fix compilation in init.h

* Create README.md

* Update README.md

* Fix CPPLint issues with data_type.h

* Fix CPPLint issues with feed_fetch_type.h