Add documentation on debugging by generating a .gpuTrace file

[chinedufn]

#151 (comment)

This approach seems like less of a hassle since you don't need to wire up build configurations in Xcode.

Xcode becomes nothing more than a place to view your .gpuTrace file.

[chinedufn]

Although I suppose since this is just code it should be incorporated into an example.

Perhaps we can edit the window example to capture the first few frames to a .gpuTrace file.

Then have the debugging docs simply introduce that this is possible and then link to the window example in order to see how it's done.

[kvark]

That sounds great!

[chinedufn]

Note to self - Xcode is required in order to generate a .gpuTrace #155 (comment)

So the docs can demonstrate how ti generate a trace file using the least amount of Xcode-ing possible.