Add interface implements annotation

I want use `@interface`,  `@implements {Type}` annotation in my company projects.

these are Google Closure Compiler jsdoc annotations.

i heard that you want add this feature to 3.4.0 but we need this feature 

so i add some codes for this. please check.

thank you.
100px is not enough text 'implemented method' to method properties.

for example, i want notify to user that this method implement specific interface.

```javascript
/** @interface */
function ILayer() {}
ILayer.prototype.move = function() {};

/** @implements {ILayer} */
function MyLayer() {}
MyLayer.prototype.move = function() {...};
```

![jsdoc__class__mylayer](https://cloud.githubusercontent.com/assets/1061205/3791138/8c037dd6-1b2a-11e4-96e8-ab50137ab002.jpg)