Enable tag bubble eye candy for Qt5 and Mac

This works when building against Qt5, so no reason to hide the cute
bubbles from our Mac users anymore.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Carefully create some forced margins

We don't want to waste space, but we don't want things to be too crammed
together, either. Especially not having horizontal margins for text can
look very awkward.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>