Provide a general tool for converting Caffe models.

[qingqing01]

• 1. A general tool caffe2paddle.py which can be used to convert most of Caffe's model.
• 2. Verification method to verify that the accuracy of converted model is correct.
• 3. Usage document.
• 4. Provide a ResNet model based on ImageNet.

[qingqing01]

• The tool to convert Caffe's model can refer: Paddle能否加载caffemodel，或者有没有工具将caffemodel转成paddle可加载的格式？ Paddle#964