3d viewer doesn't propagate to other selections, no need to check.
graph widget doesn't propagate, no need to check for propagation chain.
Move common function to utils.
Many fixes to the selection widgets' push system.
Fix reloading of skeletons.
selection table: fix toggle all visible

Performs the operation in a batch, and correctly hides/shows
synapses and text (text is only hidden, not shown).
And doesn't hide/show all selection tables at once!