normally this is used as strict task history, meaning no running
tasks included. But we can have running tasks in PBS here, so at
least avoid that they're shown as error.
Also add a refresh button as a simple workaround to the auto-refresh
problem, which isn't straightforward to solve with the buffered
reader we have here.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
