Log Message:
Changes 2.3.12:
Lib
* Removed tabs from various modules to make things work with python -tt.
* Quick fix to ldif.is_dn() to let multi-valued RDNs pass as valid.
  Is too liberal in some corner-cases though...
* Fix to ldif.is_dn() to allow dashes in attribute type
* ldap.open() now outputs a deprecation warning
* module-wide locking is now limited to calling _ldap.initialize().
  Still ldap.functions._ldap_function_call() is used to wrap all
  calls for writing debug log.
Modules
* New LDAP options available in OpenLDAP 2.4.18+ supported in
  LDAPObject.get/set_option():
  ldap.OPT_X_KEEPALIVE_IDLE, ldap.OPT_X_KEEPALIVE_PROBES,
  ldap.OPT_X_KEEPALIVE_INTERVAL,
  ldap.OPT_X_TLS_CRLCHECK, ldap.OPT_X_TLS_CRLFILE
Doc
* Various small updates/improvements