* fix 2.0-beta bugs

* update pretreained path

* add extract_weight.py

* fix some bugs

* update configs

* add esrgan model, refine codes

* refine codes docs

* fix pix2pix to_tensor

* fix apps

* refine code

* test

* fix apps

* update readme

* rm unused code

* fix apps output when input is image

* clean code

* update requirements.txt