Hi Dave,

I'm using StakKit and love it, but when I tried to include it in managed objective-c project I get following message

> objc[2411]:
> '/Library/Frameworks/StackKit.framework/Versions/A/StackKit'
> was not compiled with -fobjc-gc or
> -fobjc-gc-only, but the application requires GC

I tried to compile the source with `GC` supported but it wasn't compiled.
Could you guys make it compatible with `GC`

**And also can you add `Gravatar` url for user in `SKUser` Entity ?**

Thanks.