Try to limit generated atom names to the / directory

This is necessary in consequence of issue #2.
3 jobs for master in 2 minutes
Status Job ID Name Coverage
  Build Src
passed #9047
build:src

00:00:21

 
  Build Pkg
passed #9048
build:pkg

00:01:13

 
  Upload
passed #9049
upload:pkg

00:00:26