Rust Pathtracer

I didn't modify your code just adjusted it to compile in the Rust nightly.

Generating a 128x128 image with 16x16 samples per pixel.

Rust (rustc -O): 10s

Go (go build): 37s

Generating a 256x256 image with 16x16 samples per pixel.

Rust (rustc -O): 40s

Go (go build): 2m39s

Rust source: http://paste2.org/FCvdbKpC

Go source: http://paste2.org/cmHJfWYw

i7-2670QM CPU @ 2.20GHz -- Linux Mint X64