Add action on click.

Example : http://jsfiddle.net/CDLXE/5/
# Click on blue part
Add three Features (Relative font-size, label in donut, and number shortener)

* Relative font-size : permit to avoid summaryTitle or summaryNumber exceeds the donut.
* Label in the donut : like tip, but title is set in the summaryTitle <p />.
* Number shortener : e. g. to print 200K rather than 200000 (or 200M rather than 200000000).

Example for the first two features : http://jsfiddle.net/CDLXE/6/
Example for the last one : http://jsfiddle.net/CDLXE/7/
Try to get the perfect font size an other way (with a setting rationFont to adjust un function of your font configuration).

Example:
http://jsfiddle.net/CDLXE/8/
ratioFont of 2.1 is net bad for Oswald with the default letter spacing (firefox 29 in the test in JSFiddle)
rationFont of 1.72 is not bad for Helvetica Newe...
Merge pull request #2 from RobinDev/master

Two commits : Add action on click and Add 3 others Features