Properly handle start_tls in pynslcd
Implement PAM session handling in pynslcd

Just like in nslcd this doesn't actually do anything with the session
ids except generating them.
Implement config request handling in pynslcd

This allows the PAM module to request the pam_password_prohibit_message
option for denying password change.
Fix handling of pam_password_prohibit_message in pynslcd
Handle the nss_initgroups_ignoreusers option in pynslcd
Handle the nss_min_uid option in pynslcd
Use cleaner import and get rid of uid2dn function in pynslcd