Area Nodes and More cleanup

CHOREs

• Cleaned up the docs a bit. Will get them in better shape coming up
• Cleaned up transparency handling in canvas rendering
• Parallel Coordinates example uses canvas to show improved canvas performance (but the actual code doesn't reflect the change because it's manual instead of automatic, which I will fix)

FEATURES

• NetworkFrame now renders hover areas for area type nodes (circle pack, treemap and partition) and it's available in other modes if you send hoverAnnotation="area" in contrast to earlier when these network types used voronoi based on centroids. So the hover behavior should make a lot more sense. Are hover on edges is not currently supported.

FIXES

• More frame props properly listed
• OrdinalFrame connector styling sends the right data for canvas styling