Created by: ceci3

pre PR: https://github.com/PaddlePaddle/PaddleSlim/pull/416

work in this PR:

• ✅ accuracy model
• ⭕ search process (evolution search)
• ⭕ latency predict (support dygraph latency compute)
• ⭕ flops predict(support dygraph flops compute)
• ⭕ add document