* Remove API: squeeze
	Modify the funcation all of squeeze.
	Use paddle.squeeze to replace paddle.fluid.layers.squeeze

* Remove: squeeze
	fix some modifications which are not needless to the original
format

* Fix the function call of 'squeeze' from old style to new style.

* modify the call of squeeze from old style to new style

* Modify the call of squeeze from old style to new style

* replace squeeze with paddle.squeeze

* modify the nn.py based on the review suggestion

remove a redundant comment.

* remove one comment which is not necessary