Close Tabs Button

[apiweb]

I think it would greatly facilitate the use of the software if they were included on each tab a button to close it. I know there is a menu item that makes this functionality, but I think it would be easier and faster if each tab to have its own button, similar to a web browser.

I thought I'd suggest adding a button to "Add New Tab", but this menu is now easier to find, and has also implemented a shortcut to it in the previous commit (Ctrl + T), so I guess this would not be necessary at this time.