1377 - Blacklist dependencies from SCM tracking

Git excludes dependencies from commit. 
Mercurial just shows a warning because it doesn't support excludes on commits. Just hgignore
"What if there is already a line break at the end of the file? It's better to overwrite the file completely - and make sure there is always a line break at the end of file while at it."

    exclude_file.seek(0)
    exclude_file.truncate(0)
    exclude_file.write("\n".join(exclude_file_content) + "\n")