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.
Also: An interface could declare properties that aren't methods, right? For example, you might want to say that an `ILayer` implementation must have a `color` property.

For that reason, consider renaming this `propertyInfo`.