nfroidure/svgicons2svgfont — pull request #22 by renatoi (2014-08-12 19:13:44+00:00)
Title: Empty value for x1, x2, y1 and y2 should be zero if NaN.

Not sure if it's the best fix but it fixes the problem reported in: https://github.com/sapegin/grunt-webfont/issues/158