Merge pull request #11 from deseven/master

New function: drop root privileges
Small cosmetic fix
pwd and grp are missing on windows
os.getuid() is also missing in windows
Revert "os.getuid() is also missing in windows"

This reverts commit fc0e79df7e9d2bd1c6e28e4ca57137bc9a3b5e2e.
Fix for windows