Fixes #6117 - clean usergroup cache

Dependent destroy was missing on through association from user side.

Fixes #5810 - fixes issue with incorrect page titles

fixes #5834 - Hosts: . in the name is invalid - user is told this but the UI adds one anyway

fixes #6030 - update list of VMware guest types

fixes #5963 - fix Role has_permission? function

fixes #5869 - permit accents in user names on Ruby 1.8

fixes #5965: removed 8443 port from the suggested ovirt url

Fixes #5696 - Allow taxonomy and roles display

Fixes #5946 - Only call fact_name_class.maximum if necessary.

fixes #5836 - Welcome page - missing rel attribute