Connect quit/close signals by default
Connect quit/close signals by default

Change-Id: Ib43ad28241c8b53b00c579d0d96d91c8fa868486

OpenChemistry/avogadroapp,ghutchis/avogadroapp,ghutchis/avogadroapp,OpenChemistry/avogadroapp,OpenChemistry/avogadroapp,ghutchis/avogadroapp,ghutchis/avogadroapp,OpenChemistry/avogadroapp