Markdown converter using pandoc

[cloose]

Add a new MarkdownConverter implementation that uses the pandoc to convert the Markdown document to HTML.

pandoc is a Haskell library and a command line tool. So we have two options:

• Use QProcess to call the command line tool
• Use an existing or create a C binding for the Haskell library

This maintaining a binding is very time-consuming, we should go for option 1.

[sunnyolives]

I suppose there would be a dialogue prompt where all pandoc arguments are specified?

What about a pdf converter?