autoscale now works with more than one data plot

Previously autoscale only looked at the first plot of data
to calculate the new axes settings.

The Energy Graph on the Interactives Browser page is
one place where three plots are graphed at the same time.
update to fork of jsdom 0.5.6

Also specifying html level2 emulation in env.js

Now using this fork checked out as submodule in test/vendor

  concord-consortium:canvas-behaves-like-div

See pull request:

  https://github.com/tmpvar/jsdom/pull/608
more grapher refactoring