#495 New functionality: close all to the left/right

[Andreas Jonsson]

https://sourceforge.net/p/notepad-plus/feature-requests/2308/

Adds two choices in the tab context menu for closing all tabs to the left (or right) of the current tab.

Note: I have tried to get everything right in the localization module, but I'm not so familiar with it so there might be something missing.

[Don HO]

Adding 2 more items in File menu causes a problem of order of recent files history (if any).
Adding "Close more" submenu then put 3 commands (+ Close all but this) into it solves the problem.

Don