* Fix warnings from Logging, enable Plan memory to take external memory

* fix external memory id

* fix graph

* fix glog

* sync logging improvement from dmlc

* [PASS] include knullop info in plan memory

* Bugfix plan memory, fully support mxnet

* [INFER] Enhance backward op policy

* [SYMBOL] add list inputs

* relax graph attr to enable copy-on-write

* Update tuple to be compatible with mshadow

* Move set error message to C API

* simplify with using

* updates to shape inference

* Add unnamed namespace to the implementations

* [SYMBOL] Enable inference of Auxiliary data, rename list_arguments to list_inputs