Removed download_function

Putting back the old path. I need to be able to debug it in my desktop

Added some documentation
4 jobs for issue-50 in 31 minutes and 9 seconds (queued for 10 seconds)
Status Job ID Name Coverage
  Build
passed #135389
docker
build_linux_27

00:21:25

passed #135390
docker
build_linux_36

00:18:32

passed #135391
macosx
build_macosx_27

00:27:59

passed #135392
macosx
build_macosx_36

00:24:12