New Tab For Android Autor: mortalis

Adds the New Tab button to the URL bar.
Addon settings page allows to change the new tab URL. It should be in format
"http://server.domain" like in "https://goolge.com".

'about:home', 'about:addons', and other similar URLs don't work according to the addons development documentation.

(https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/tabs/create,
see the 'url' parameter)