ENH: Add comments for memory and memcpy

Check Insufficient Alloc in tensor

Refine device context and fix GetPlace()

fix dropout and clipping settings in layer helpers.

Fix bug for multi-GPU inference.

* fix recordio split and task passes

* update for pre commit

* update

* update, still need to sync client wait for pass end.

* able to sync passes for task dispatching

* update to comment

* update

* fix yapf check

* why local pre-commit fails? version is the same

* fix race condition

* update

* fix race condition

* this still have duplicate problem in unit test

* update

* update

* update by comment

* update

fix bug in OpKernel register macro

ENH:  for clarity, change DLOG to VLOG

ENH: Refine Tensor and Add CopyFrom

Make network op

Fix bug in SequenceSoftmax

Also remove operator bool in Error. The Error should be removed
later because it is not necessary for Paddle. We are now using Enforce
to handle error.

* default learning rate, temperary fix

* update

enable v2 automatically sets using cudnn-batch norm.

"fix gen list"

Make PADDLE_ENFORCE and PADDLE_THROW catchable

Feature/middle level net api

Make C lib in `paddle.v2.master.client` lazy load