nullCrash. 各处搬运的处理NSNull的方法，解析json遇到null用https://github.com/nicklockwood/NullSafe 字典遇到nil用https://github.com/allenhsu/NSDictionary-NilSafe，数组遇到用。。。百度上搬运的，在此做个备忘

Problem

The full read on this project is a sign-in away — what it solves, who it serves, and where it sits in the market.

Audience

The full read on this project is a sign-in away — what it solves, who it serves, and where it sits in the market.

Market

The full read on this project is a sign-in away — what it solves, who it serves, and where it sits in the market.

Pricing

The full read on this project is a sign-in away — what it solves, who it serves, and where it sits in the market.