use size as pixel for width/height instead a multiplicator

[paulknulst]

size should be used for determining the size of the produced SVG instead of being a multiplier

as i understand the documentation it should work like my implementation:

size (png and svg only) — size of one module in pixels. Default 5 for png and undefined for svg.

[technoknol]

Any updates on this ?

[paulknulst]

i fixed it within my commit. so feel free to use my fork