Capture atomics in closure

[bobbersen]

Thanks for pointing that out, it's a really helpful example for me. I just 
started getting into weave and laser recently and I'm pretty sure I would 
sooner or later stumble over a similar problem. I'm planning on implementing 
some algorithms using weave to compare performance of various programming 
languages. With all the benchmarks you provide in the repo I'm pretty sure I'll 
get a grasp on how to use it properly.