Added additional configuration settings and contact page

Added website logo in website configuration along with some basic social media links.

You can display the value of the settings in theme by doing following:

`{{ Setting::value('website_logo') }}` Or `{{ @$website_settings['website_logo'] }}`

`{{ Setting::value('facebook_link') }}` Or `{{ @$website_settings['facebook_link'] }}`

`{{ Setting::value('twitter_link') }}` Or `{{ @$website_settings['twitter_link'] }}`

`{{ Setting::value('gplus_link') }}` Or `{{ @$website_settings['gplus_link'] }}`


For the contact page, you can specify that a page is contact page by checking the "Is Contact Page" checkbox. Then, you can also specify the map co-ordinates if you want. A sample view of the contact page can be found in `app/views/public/default/contact.blade.php`

**Note:** A field "extras" has been added to the posts table. If you want to work with an existing database, be sure to add an "extras" field to the posts table in the database, with type text and nullable property. For new installs, it will automatically be generated in DB.