Remove necessity to append .md to directories #10
Description
The performance boost shouldn't be to big on normal projects like
- https://goessner.github.io/microjam/
- https://goessner.github.io/g2/
- https://goessner.github.io/Mechanismentechnik/
and I do think it is confusing to add file endings to directories.
A better approach may be to add a blacklist (or whitelist?) to the microjam object in the package.json, or to
check directories for a microjam.ignore file.