[sailfish-browser] Add private data clear options to browser settings

This will add "clear history", "clear cookies", "clear saved passwords",
and "clear cache" options to the browser settings.
Change order of default search engine and privacy button

Once we have more settings sub pages the button should be changed
to a background item.
Merge pull request #110 from rainemak/clearHistorySetting

[sailfish-browser] Add private data clear options to browser settings