Add shortcut that can pop out tabs to a new incognito window

[stefansundin]

If the tabs are already in an incognito window then they will be popped out to a normal window. This obviously loses the navigation history as that cannot be preserved (essentially the tab URLs are just recreated for the new window).

This fixes #22. As this is probably a rather uncommon use case, I do not think I want to merge this PR and release this feature in the main extension. And it requires reintroducing the tabs permission, which I just got rid of in v1.6.0, which makes me like it even less.

To download and use this, simply follow this link to download a zip file of the branch: http://github.com/stefansundin/duplicate-tab/archive/pop-out-to-new-incognito-window.zip

Extract the files in the zip file. You may want to disable the normal "Duplicate Tab Shortcut" extension first, if you have it installed.

If you are using Chrome, open the Chrome extensions page and enable Developer mode. Then click the Load unpacked button and select the chrome folder. Verify that the version of the loaded extension is 1.6.1. Go in to the extension details and enable "Allow in Incognito" to enable the ability to use this new shortcut to move incognito tabs into a normal window. Set up the keyboard shortcut as you normally do.

If you are using Firefox, open about:debugging#/runtime/this-firefox and then click the Load Temporary Add-on... button and select the manifest.json file in the firefox folder. Then open about:addons and navigate in to the extension details. Verify that the version of the loaded extension is 1.6.1. Scroll down and enable "Run in Private Windows", otherwise this feature does not work at all in Firefox. Set up the keyboard shortcut as you normally do.

Enjoy. Please feel free to discuss this feature here or in the original issue #22.