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
* Add RareStyle qrc with the icons needed for comboboxes and spinboxes
* Add images as svg
* Refactor `styles` to `resources` since it contains more things now.
* Add stylesheet folders, each folder must contain a `stylesheet.qss` file.
* Don't use QResources, instead add an identifier in the qss url() which can
replaced later with the full path.
* Update RareStyle with SVG images for better quality.
