SystemTrayMenu 1.0.21.0

Changes:

• #215: [Feature] Main Menu Loading icon and fix warning / clean code
• #207: [Feature] Clear internal icon cache if too big
• #206: [Feature] Settings - Add button to open root folder
• #204: [Feature] Improved performance
• #69: [Feature] Mouse disturbing while using keys
• #214: [BUG] Rare flickering in darkmode and open same item several times
• #213: [BUG] NullReferenceException when missing default browser
• #209: [BUG] Icons of shortcuts not displayed correctly