Typo in triangle()

[fjenett]

This line in triangle():

, x1, x2 // start of path

https://github.com/MrRio/jsPDF/blob/master/jspdf.js#L1154

should probably be:

, x1, y1

[dvdotsenko]

@MrRio

This is likely my fault. This patch https://github.com/fjenett/jsPDF/commit/3c38a5bcf4d813db3facecc2ad15b4f8e0f6994e makes sense.