1. Combine 'open_files', 'multi_pass_reader' and 'threaded_reader'
together to make the new 'open_files' interface.
2. Add some docstring.
3. Simplify interface names of 'create_XXX_reader', e.g, rename
'create_double_buffer_reader' to 'double_buffer'.

Merge branch 'develop' of https://github.com/PaddlePaddle/Paddle into modify_readers_to_fit_parallel_executor

Update reader

Move filemanager to `edl` repo.

Update release doc

1. Removes MultipleReader's multi-thread support, for we have got
ThreadedReader.
2. Rename MultipleReader to MultiFileReader

fix compiler error on `tensor_py.h`

fix missing core.so on mac

* Update source files.

* Update headers

* Update

* Update

* Update

* Update

* Fix a CMake dependency

* Fix cpplint errors with paddle/fluid/platform/gpu_info.*

* Update

Fix a minor bug for distributed_spliter.round_robin

* Correct inference

* Update

* Update

* cpplint test and add tesnor_py_test.cc

* Update

* Update

Fix cpplint errors with paddle/fluid/recordio

Also fixed typo and comments.

* initial commit

* fix error

* fix typo and order

* change from hgemm to gemmEx

* fix cpplint

Expose CUDAPinnedPlace to Python