anchor.diff:  if exist extensions\perspectiveGraph\ (
       cd extensions\perspectiveGraph
       call git fetch --all
  +    call git checkout master
  +    call git pull
   ) else (
       call git clone https://github.com/tagspaces/perspectiveGraph.git extensions\perspectiveGraph
       cd extensions\perspectiveGraph
  
positive.code: if exist extensions\perspectiveGrid\ (
      cd extensions\perspectiveGrid
      call git fetch --all
  ) else (
      call git clone https://github.com/tagspaces/perspectiveGrid.git extensions\perspectiveGrid
      cd extensions\perspectiveGrid
  
negative.code: if exist extensions\viewerText\ (
      cd extensions\viewerText
      call git fetch --all
      call git checkout master
      call git pull
  ) else (
      call git clone https://github.com/tagspaces/viewerText.git extensions\viewerText
      cd extensions\viewerText
  