pClock size handling

[dhornbein]

The pClock needs to adjust it's size to fix the viewport.
It will have to take into account it's current size, the amount of data, the user defined options for line width and radius. Then calculate the best way to fit it on screen.

Let's discuss those parameters here.

[thiagodemellobueno]

This will probably do the trick.
http://raphaeljs.com/reference.html#Paper.setViewBox
I sort of implemented it, but its a bit tricky, probably set up a feature branch for it.

[thiagodemellobueno]

I set up the zoom on mousewheel action... there's tweaking to be done, but its a proof of concept.
Raphael zooms oddly, line-weights seem to scale up.
Rendering is superfast though, so we can redraw on zoom as well (though, then why not just redraw instead of using setviewBox... ) in any case we probably want to tweak strokeweights on zoom. Haven't found a sweetspot.