Add more optimizer

Update the command readme

Add sequnece labeling predict

Merge branch 'develop' of https://github.com/PaddlePaddle/PaddleHub into add_sequnece_labeling_predict

Update the file readme of demo text-classification

Fix the bug that user couldn't choose to use gpu whether or not

* Update the command download so as to show search tips when module/model can't find

Modify the command install

* Inform user the installed version of the module

* Update uncompressed model name

fix demo sequence-label