Chen Zhutian 27986da0aa add request.body (#11395) ...

* add request.body

* Update koa-bodyparser.d.ts

According to the documentation of `koa-bodyparser`:
```javascript
 // the parsed body will store in this.request.body
 // if nothing was parsed, body will be an empty object {}
 ctx.body = ctx.request.body;
```

Therefore the `body` property will exit in the `request` object.
Changing the `body` property from optional to required can also fix the conflict problem in Koa's declaration file:
```ts
 class Koa extend Request, Response {}
```

2016-09-28 21:24:41 +09:00

..

koa-bodyparser-tests.ts

…

koa-bodyparser.d.ts

…