Number tabs when the ctrl/alt/cmd button is held.
A tool for those who uses ctrl/alt/cmd+number to jump between tabs. Display page number when you hold ctrl/alt/cmd key.
* Now the extension also works with pages having no favicon.
* Fixed a bug that the number is not shown on some pages, such as google group.
* Show tab numbers when alt is held in non-Mac system.
* Fixed a bug that tab numbers stay if page is closed with ctrl/cmd+w.
* Fixed a bug that tab numbers stay if control is switched to another window when ctrl/alt/cmd is held.