Patchset 2021.1

This patchset contains the following updates:

• Code cleanup: Remove empty lines
• Code cleanup: Remove superfluous newlines in trace code
• Code cleanup: Fix indentation and remove stale lines
• Code cleanup: Convert refresh_tacho_view() to a static function
• Fix invalid state flag
• Avoid implicit conversions between XfcePanelPluginMode and GtkOrientation
• Update and sort .gitignore
• Update copyright year in about dialog
• Increase icon size in about dialog from 32 to 48 pixels
• Code cleanup: Move a couple of variable declarations to inner scopes
• Fix accesses to destroyed widgets when changing the panel orientation
• Fix invalid order of widgets after changing panel orientation