Recommended core Tweaks and fixes

FEATURED
* I have gone through each part of the core and tweak around to fix the found hard-links which are not good for WooCommerce obviously.
* Some functions like `get_option( home )` & `get_bloginfo( 'text_direction' ) === 'rtl'` with `home_url()` & `is_rtl()` respectively which are informed by WP codex to use instead of.
* Additionally, I have done better alignment for Tweet button with `margin-top: -3px`. @claudiosmweb there's a PR https://github.com/claudiosmweb/woocommerce/pull/1 already for your work in 2.3 UI focus for better Tweet Button alignment with button-primary.

**Note:** I have managed to delete the below snippet for Badge which is unused now in the Welcome Page
```php
// Badge for welcome page
$badge_url = WC()->plugin_url() . '/assets/images/welcome/wc-badge.png';
```

Though, I have also managed to updated the changes with `grunt dev` so don't worry for i18n and assets changes.