Log examine page load & render time in the console

Because you are what you measure.

I'm seeing load & render times of ~2500ms when I run cycledash locally. It's no different when I undo the parallel XHR change. This means that parsing the VCFs and rendering the page is the bottleneck, it's not network activity.
If we're concerned about profiling the loading time of the page (and we should be), using the Profile window in Chrome is far more informative, and doesn't clutter the code. We have this for free already!

If this is needed, it seems like something that should be in a debug or development mode.