Add ability to define number of bookmarks & closed tab

When I say *number of bookmarks*, it only affect the recent bookmark list only.

Closed tab might still get some problems if the defined value is superior to the previous one and localStorage doesn't have enough items. It's hard to explain, but sometimes, when I reach the previous limit, it reset the localStorage .. So the best things to do, is to *clear recently closed* manually if you increase the number of closed tab.
It can be something automatic but I find it a bit intrusive for the user..

BTW, this might close #13