Adding a more sane scaling factor

This avoids not only odd pixel drawings, but also the issue when the last pixel
row is not a full number (thus failing to draw it.) To overcome this issue (and
perhaps this should be implemented in the code if too many folks run into the
issue) is to draw an extra pixel line, scissor the drawing area, and call it a
fish.

As another alternative, I can suggest a letterboxer/scaler, like LovePixlr:
https://gist.github.com/josefnpat/08e463d0dc82e71f5a3d
Adding a license to the repo: zlib/lpng

merry xmas <3