Some renamings and documentation added

This would make AllocationRow more understandable.
Be more restrictive when discarding messages

MessagesForUser doesn't discard the messages when changing focus.
Remove the listener allResourcesPerDay

It's not strictly necessary since inside the listener is checked that
effortInput is enabled, but for consistency do it the same way as with
effortInput.
Fix bug #1644

When an allocation cannot be done, the error message on the input
disappeared because the rows were re-rendered due to reloadBindings
call. Now this call is avoided and some extracted functionality from
getCurrentRows is called.