Convert Dir-Tree Images to SVG

[tajmone]

The following PNG images, representing directory trees, could be rebuilt in SVG using Dia:

• git-branches-crop.png
• git-dir-crop.png
• objektmodell-programm-crop.png
• svn-branches-crop.png
• svn-nonstdlayout-crop.png
• svn-stdlayout-crop.png

NOTE — In the upstream repo, these PNGs can be found in the bilder_quelldaten/dir-listing/ folder, were they are autogenerated from .tex TeX sources via the docstrip utility.