dial: vendor gauge.js and related jquery plugin.

Grabbed from http://bernii.github.io/gauge.js/
MIT licence.
dial: copy gauge.js into dial.js

No changes except for renaming Gauge to Dial, works as the original
gauge view.
dial: new view, similar to gauge

Displays a vector-based gauge on an HTML <canvas> element.

Canvas elements don't accept relative widths and heights, so each time
the view is resized, we have to recalculate the absolute size in pixels
and update the canvas' properties.

When the gauge's upper limit isn't defined by the user, it is updated to
the biggest value encountered. To make this behaviour understandable, I
made the decision to always display this maximum value alongside the
current one.

gauges.js has bunch of options (colors, animation speed, etc) which I
left to the default values. This can be easily polished up later on if
we feel the need to.
Merge pull request #75 from mfournier/dial

New "dial" view, similar to "gauge"