file yst/index.yaml is created based upon the md file in root
added gitignore
func _processMd() now ranges over a (short) slice of mDer's
fixed the creation of sym links in yst/files/
creates empty md files in yst/
creates yst/build.sh using a text template.  Script yst/build.sh can by run to create the final site in yst/site/

need to improve the site styling a little bit, otherwise this part is nearly finished

need to check whether ./ystyd can be run from another location to create a site!