Feature/stats per lane fc instrument

This implements a whole bunch of API handlers for getting per instrument time series of various statistics.

It also has corresponding plot handlers and a new web page `/sequencing` which shows all this information as once. Screengrab:

![26e5630b-8c05-46a5-ad2a-91e58065eb99](https://f.cloud.github.com/assets/668803/328005/79bfe23a-9b89-11e2-8ad2-fcf427290af8.jpeg)