lines between consecutive rectangles.

[NikEfth]

Hi all,

I create a new function in Board to draw 2D images stored in vectors. I did so, by printing a rectangle for each pixel. The problem is that a wireframe(see attached) is visible in the eps images. Is there a way to avoid that. I would love to see this feature in the library, after proper revision. I will applied a PR #7 so you could review the code.