- many updates in fabfile
- new ldap_users_and_groups functions:
  .preparedb: Prepares the needed groups and permissions.
  .sync: Runs preparedb. Creates Users and Groups if necessary, synchronises Users and Groups relations.
  .test
- removed the fixture users.yaml as its need is replaced by preparedb
- back to the LDAP groups mirroring
- added LDAP groups caching of one hour instead of at each request
- added LDAP access also in development environment