Enhancement: Implement LRU tab closing ordering

[macta]

When you open a new tab - e.g. click on a page in your knowledge base - it opens a new tab by default. If you have clicked on the wrong one and so close it (meta-w) it doesn't return you back to the knowledge base tab, it goes to the last one in the list, which is very disorienting and inefficient if you want to click on another page instead.

(aside - when it opens the new tab, it doesn't focus this in the tabs list - so its not entirely obvious where you are in the UI anymore - you have to know to scroll along the top tabs to see the one that is selected at the end).

[seandenigris]

I've struggled a bit with both of these and would appreciate such enhancements