support markdown files

[7flash]

Currently I have a documentation folder in markdown, and then to use semantra I have to do pre-processing from the folder into pdf (each file becomes a separate page) - would be amazing if semantra already supports this and I can just drag&drop a folder

[satonotdead]

Markdown is the common standard and openly used on the internet.

I'm OK with PDFs because it's the commercial standard but I think Sumatra is a project that values the foundation of open-source from the base.

I hope this will be implemented, I think the vast majority of users have their personal notes on Markdown files instead propietary formats :)