tweener: Also consider delay when disabling animations

'time' is not the only timing parameter for tweens, in order to
really disable animations, we need to override 'delay' as well.
iconGrid: Move code around a bit

The scale passed to _updateChildrenScale is exclusively computed from
properties, so it can be moved into the function itself - as the scale
now becomes a mere detail, rename to a more appropriate _updateIconSizes
at the same time.