Add `make print` command

[hayribakici]

This PR fixes #1

This PR adds a new print target, that makes all monospaced fonts, url and links black. In order to be able to make the monospaced font also printer friendly, a new yml property has been introduced: monospacecolor to set the color of the texttt command.

The print command replaces the colors of the above mentioned yml properties to black with overriding the values in the yml-file with the --metadata command.