Support custom CSS for preview

[johnsheehan]

I'd love to be able to drop in a style sheet that makes the preview match the styles of my site.

[shiftkey]

This was something we worked on a long time ago but I'm not sure what state it is currently in.

https://github.com/Code52/DownmarkerWPF/blob/master/src/MarkPad/Document/ParsedDocument.cs#L45 (yes, I'm pointing at code instead of docs - for shame).

Given it's likely to be scanning the root directory, how would you imagine configuring it?

In any case, I need to revisit the documentation.

[johnsheehan]

MarkdownPad (my previous favorite windows markdown editor) just has a text box in the settings for the CSS rules. That works for my needs.

[shiftkey]

I'll contrast that with what we currently have - there's probably a balance in there somewhere.