Get also closed tasks and set their valid from and valid until dates.
Rename Charm to EndoCharm and change the organization to Endocode.

That way this application will have separate settings, databases,
D-Bus addresses and whatnot from the upstream KDAB Charm.
Instead of disabling "Edit task" action, change its role to "View task".
Disable task selection checkboxes when backend is not capable to modify tasks.
Small updates of Chili notes.