Use fixed width font for editbox

[ffes]

I received this request per email:

I would make a request to
improve visibility of text for the code in the edit box. It's possible
to change the font by a monospaced or maybe the ability to choose any font?

[icefront]

This feauture would be very useful. For the start the font doesn't matter...
I always have hard times entering the iljI characters, those are too narrow!

[amias-scribe]

Fixed width font would be helpful for me, as would the ability to type a Tab in the edit box. Right now I use a "scratchpad" document to create snippets and copy/paste but it would be nice to be able to edit more on-the-fly.