* wkhtmltopdf from vendor rather than ubuntu upstream
* removing xvfb
* fixed dependency issue for wkhtmltopdf
* Fix formatting, add --no-progress to wget command
The `md2pdf` bash script created during the Docker image build was
invalid. For some reason, it was scrapping out the line break:
```
root@92820d4e9bc1:/resume# cat /usr/bin/md2pdf
```
As a result `md2resume` was failing silently. Also, it was not possible
to run wkhtmltopdf standalone headlessly inside the container. These
changes allow wkhtmltopdf to be run headlessly and fix the issue with
`md2resume pdf`.
Benedikt Franke
Erik Waibel
KK
danielklim
Matheus Marchini
spawnia