Problem with Webkit / wkhtmltopdf and default height value

I've just added a pull request (#218) to change the "height" in the "defaults" object from 100 to 1. This is to solve a problem with blank spaces between EAN13 and EAN5 add-on codes, where the default height results in unpredictable rendering with wkhtmltopdf (webkit engine) - barcodes with a height less than 100 will still render at the default of 100 because of this blank space.

Start by reviewing the defaults object and pull request #218, then reproduce the EAN13 and EAN5 add-on rendering with wkhtmltopdf. Done means barcodes with a height below 100 no longer acquire the default height or show unpredictable blank space.

Written by the indexing model from the issue text.