add pretrained and quant models (#442)

* add pretrained and quant models

* add slimfacenet pretrained and quant models

demo/slimfacenet/README.md

@@ -31,6 +31,13 @@
 
 如果使用预先训练并量化好的`slimfacenet`模型，可以从以下地址下载
 
+[SlimFaceNet_A_x0_60预训模型](https://paddlemodels.bj.bcebos.com/PaddleSlim/SlimFaceNet_A_x0_60_112x96.tar)
+
+[SlimFaceNet_A_x0_60量化模型](https://paddlemodels.bj.bcebos.com/PaddleSlim/SlimFaceNet_A_x0_60_112x96_quant_post.tar)
+
+[SlimFaceNet_B_x0_75预训模型](https://paddlemodels.bj.bcebos.com/PaddleSlim/SlimFaceNet_B_x0_75_112x96.tar)
+
+[SlimFaceNet_B_x0_75量化模型](https://paddlemodels.bj.bcebos.com/PaddleSlim/SlimFaceNet_B_x0_75_112x96_quant_post.tar)
 
 ## 3. 启动`slimfacenet`训练任务