Updated to v1.8.140.1

Changes / v1.8.140.1

• Fixed icons in context menus.

Changes / v1.8.140

• Added an additional set of icons for context menus. This is not a replacement for existing icons, but a minimalistic alternative with better support.
• The userContent.css file has been tidied up. This should make it easier to add third-party styles.
• Some options are now compatible with vertical tabs. See README.
• The web page transparency option has been improved. New options have been added. Still in experimental status.
• Improved support for tab grouping.

This version of the style will be updated only to fix bugs. No new features will be added.