QToolButton is not really designed to be used in the way we did and since
QPushButton supports having a menu attached to, we can replace tool buttons
in most cases.
* Fix the presentation of the TabButtonWidget by updating RareStyle's css
* Reduce the size of the top tab bar to save vertical space.
* Remove infoLabel property
The static stylesheet properties are always applied. If there is a theme
stylesheet to be applied, they are appended in the end of the theme
stylesheet.
This removes stylesheet properties from the library widgets, some special
buttons and the queue worker labels.
To update the static stylesheet first edit `rare/resources/static_css/stylesheet.py`
and then execute it as a script.
