minor fixes to host show page

added vm tab

host show folded into tabs.

fixes #1678 - nested hostgroup selector for templates.

ptable, arch and medium errors where not always visible in the UI when saving a host

code comments typos

ensure that autosign entries are removed when using ssh based provisioning.

this is required, as we changed the ssh part to be post db commit.

configTemplate returns nil if a template is not found

added classes-filter to the puppet classes selection page. fixed the selected classes sort.

also fixes #1675

Since ssh script now runs post commit, we can not update any attributes within the save method