* adam sparse support

* fix gpu build error

* fix ci

* fix ci

* fix adagrad sparse update bug

* fix gpu build error

Remove unused model.py

* "fix accuracy kernel bug"

* "relauch ci"

Fix conv2d bias

Add dilations for conv2d and optimize conv2d code

Enable manylinux builds

* fix gitignore

* refine cmake file

* add decayed adagrad python code

* fix typo and order

* small fix

The size of the bias parameter should be the number of filters.

Update the annotations of layers.py.

 Simpily demo, add paddle.default_main_program() and paddle.default_startup_program()

Feature/evaluator

Fix/reduce op

- Removed all main_program and startup_program in the demo.
- Using paddle.default_main_program() hides the implementation detail (e.g., using g_main_program) from the user, we can change the implementation in the future much easier.