Drawing example shows a black rect when showborder is setting to true

[kuoruan]

I'm using the example of custom drawing context. and find a bug when showborder is set to true.

https://github.com/metafloor/bwip-js/blob/b108cb6c2fd9ee11dd4d11c13b8b5945c12eff68/examples/drawing-example.js

[metafloor]

Looks like the two paths that define the border are not compatible with the nonzero fill rule. Both paths are defined counter-clockwise. I will have a new release out this weekend that fixes that.