SparklineSet and Sparkline work for single test sparkline
SparklineSet finds y and x values automatically from supplied data.
SparklineSet wrapper works for shared y-axis. also fixed many bugs.

also fixed python bugs. turned out it was saving state between runs because i didn't know
how python worked: vars you set in in the class definition (as opposed to in the __init__() method
are shared between all instances...i was leaking state all over the place.
Merge branch 'master' of github.com:total-impact/impactstory-analytics