Added support for better admin bar with external links

**Features:**

 * Set the `admin_bar_priority` else default `999` will be applied.
 * Don't culprit with default `admin_bar_icon`. If they want they can apply via `$args`. Condition patched.
 * Added support for `$this->args['admin_bar_links'][]` so fixes #1645 

**TODO:**
@dovy links are not clickable in framework page but when you goto default wp pages and browser those links then it's working. I couldn't understand why the framework pages is not loading link.