Support for thick pie charts

[schillermi]

Hi

I committed my changes to the master branch by mistake (sorry, my first time on git).

BR
Michael

[dnschnur]

I need to spend some more time looking at this, but one comment is that it uses the jQuery Color plugin. Flot already uses its own jQuery Colorhelpers; is it possible to use that instead, so we don't need to add a mostly-duplicate dependency?