Numerous fixes and configuration options

This pull request changes the following:

1. Changes the skin file structure to make it a non-autoloaded skin, which allows the use of resource loader, configuration options, and makes enabling the skin slightly easier.
2. Adds resource loader support
3. Adds the responsive css by default
4. Fixes some bugs with contentSub and contentSub2
5. Adds configuration options for different layout styles
6. Removes a lot of unused code and commented out output
7. Changes the dropdown for page titles to be a static localized "Page" message to ensure layout doesn't break
8. Adds configuration option to always show navbar to anons
9. Adds "Show other languages" into the navbar
10. Adds configuration option to show sidebar as a set of dropdowns, rather than a list of items
11. Fixes all errors, notices and warnings shown in php error log