Installing latest builds of wkhtmltopdf and wkhtmltoimage on linux

• Get correct version from this page: wkhtmltopdf.org/downloads.html

download=http://download.gna.org/wkhtmltopdf/0.12/0.12.3/wkhtmltox-0.12.3_linux-generic-amd64.tar.xz
wget $download -O wkhtmltox.tar.xz
tar xf wkhtmltox.tar.xz
sudo mv wkhtmltox/bin/* /usr/local/bin/
rm -Rf wkhtmltox*