Consistently use slots / signals

We started out using Q_SLOTS and Q_SIGNALS but then changed our mind.
Let's make this consistent again.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Improve readability of yearly statistics

Make the entries for years bold, keep the months non-bold.
It's still a sea of data, but this is an improvement.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Better minimum width for yearly statistics window

The Qt default was way too small.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Remove unused QMap include

This sneaked into commit 9364436264638e639c7ef2eb642783fbee6f7ea4.
It shouldn't be there.

Signed-off-by: Henrik Brautaset Aronsen <subsurface@henrik.synth.no>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>