Main changes:
● Added an option to remove extra generic frames that some apps may draw.
● Added an option to remove all focus rectangles.
● No disabled state for toolbars.
● Fixed toolbar horizontal extension indicator with HDPI.
● Don't touch toolbars whose appearances are modified by stylesheets.
● Prevent tiny busy indicators with rounded progressbars.
● More precise calculations related to shadows and blurring of menus/tooltips.
● Disabled the context menu for transient scrollbars.
● Added a low-contrast theme (KvBlender) inspired by Blender.
● Replaced the Qt methods that were deprecated by Qt 5.13.