add margin config

[feibyte]

you do nice job!
In my opinion , I would add svg margin config so that the text wouldn't be hidden when overflow.
radar-chart.js line 69: return (p < 0.4) ? "start" : ((p > 0.6) ? "end" : "middle");
should be: return (p < 0.4) ? "end" : ((p > 0.6) ? "start" : "middle");
forgive my poor english and doesn't express my thounght clearly.