another major graph refactoring

extensive additional comments

option: realTime replaced with: "dataType"

"DataType can have values of "fake", "samples", or "points"

Internally the grapher now always uses points, which is an array of two-element arrays of x,y values.

When graphs are small and responsive layout is enabled there are tooltips displayed for labels which are no longer visible.

All line graphs are drawn into the canvas layer, however selectable markers existing in a layer above the canvas.

Some functions in API are simplified and renamed.

Some examples:

  Point data consist of an array (or arrays) of [x,y] arrays.

    addPoints
    addPoint
    resetPoints

  Sample data consists of an array (or an array of
  arrays) of samples. The interval between samples
  is assumed to have already been set by specifying
  options.sampleInterval when creating the graph.

    addSamples
    addSample
    resetSamples
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
update to jsdom master: 6ed9c6bc

Includes this pull request merged into the master branch

  https://github.com/tmpvar/jsdom/pull/608
  canvas behaves like div w/o node-canvas installed